Sorry it took awhile since my last post. I hit every problem on my quest on getting the best computer for the Arcade1Up. Damn you Murphy and your crappy law. Anyways, lets get on to what I have found.
Looking at the Raspberry Pi option, it’s major weak point is the HDMI to LVDS converter, which costs $30. I know that there are some computers that have a LVDS hook-up, but there are many different kinds. After looking around, I found the ALL In One (AIO) computers. These are low cost computers that are built into the monitor. So the motherboard, HDD, and optical drive are all behind the LCD display. The motherboard connects to the LCD, with a LVDS connection. There is also a backlight circuit to drive the LEDs chains, sometimes on the motherboard. This looked like a great option, and turned out to be one, after some hard work.
I went onto eBay and searched for some AIO motherboards, and the prices varied. However, there are some great boards that I found that were in the $20s to $30s range, which had low cost APUs. I finally decided on a Dell Inspiron 3455 motherboard, with an AMD A8-7410 APU. The processor is a mobile processor that Dell put into an AIO computers. It is based on the Carrizo-L, and is 28nm. It has 4 cores running at 2.2Ghz-2.5GHz, with 2MB of level2 cache. One channel of DDR3L, where up to 2GB can be shared with the GFX. The attached GPU is the Radeon R5, with 128 cores running at 300MHz-850MHz. It has a RJ-45 port, 2 x USB2, 2 x USB3, audio in, audio out, HDMI out, memory card reader, and a wifi port connection. The board was new, and I got it shipped for $26.04. The AMD APU is by far a lot more powerful than the Raspberry Pi 3 APU and must likely the Raspberry Pi 4 APU too.
Edit: Forgot to mention that the Dell AIO MB has 2x15w stereo speaker connections. Now I don't have to worry about the mono audio on the SF2.
Before buying the board, I did do some research. The first thing I researched was what monitor(s) did it come with. There are 3 different 24” 1920x1080 LCD monitors that came with this AIO computer. A lot different than the 17” 1280x1024 LCD that came with the Arcade1Up, but I will get to that later. I pulled up the datasheet for one of the monitors, and found it used the same 30 pin LVDS as the Arcade1up monitor. Since it had the same pin-out, I should be able to get it working. I had to find a solution to change the resolution, which I did. I will detail this later. Also, the motherboard has an HDMI output. So if I couldn’t get the LVDS working, I could buy the HDMI to LVDS converter.
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I got some DDR3L SO-DIMM memory, cheap power supply, heatsink, and some Dell 3455 cables. I hooked things up, and connected the HDMI out to a monitor. I powered it up, and ran into my first problem. Dell is now pulling an Apple. Dell doesn’t want people to use cheap 3rd party power supplies, as they only want people to use their overpriced cheaply made power supply. I found out that Dell now puts a lock out chip into their power supplies. I had to buy another power supply. I found out that people have cracked this lockout, but the Dell power supplies were about the same price. More expensive then a regular power supply though. This was the first major problem I ran into.
The first part I looked at was the backlight driver, that was on the MB. Two of the three LCD panels have 3 LED chains, while the last LCD panel have 4 LED chains. After doing some research I saw that they control this by the wire used to connect the backlight to the MB. If 3 LED chains, then 2 pins were grounded on wire, and 4 LED chains, then 1 pin was grounded. So there are 2 different cables to connect the back light to the MB, made by Dell. Since the monitor in the Arcade1Up, has 4 LED chains, I needed to ground one pin. Also I found out that you need to use the cable, or ground 1 or 2 pins. If not, then the MB will not boot, and give you a monitor error.
But in the end, it didn’t matter. If you read my other post, you would know that the LED chains in the Arcade1Up LCD panel need a low voltage with a buck circuit, where this driver drove high voltage, using a boost circuit. So I decided to use the backlight driver that came with the Arcade1Up, but modified to make it dimmable. This info is in my last post. The backlight driver chip was an OCR554 chip, and I couldn’t get/find the datasheet, even after emailing the manufacture. This was the second problem, but not that big. I stopped working on the backlight and switched my intention to the LCD resolution.
Link to my Last Reddit Post
I first decided to figure out how to connect the LCD to the MB. I used the original LVDS cable and cut the wires going into the 2x15 connector, on the Arcade1Up board side. I then soldered the wires into a 30pin 0.5mm & 1mm pitch flat wire breakout board. Then used a 1mm pitch 30pin FFC wire to connect the breakout board to the MB. This worked out great, and gave me the extra length I needed. If people need, I can post the pin out of the 2x15 connector.
Now with the MB connected to the LCD, and the backlight driver connected too, I tried booting it. Of course, this failed, and the LCD just kept on trying to sync to the wrong resolution. I began to try to think how to change the resolution. I began to look at the LVDS connection. I knew it used a Realtek eDP to LVDS chip, before buying the MB. I could see it in the pictures of the eBay sale. I also saw the EEPROM next to the converter. This was my first idea of attack. When I got the board, I found out it was a Realtek RTD2136R eDP to LVDS converter, using a ST 24C64WR EEPROM, as the Boot ROM.
I used a Arduino Uno to download the Boot ROM. I couldn’t find or get the Realtek RTD2136R datasheet. It is controlled by Realtek and manufactures. After doing some research, I found out that the chip uses an old 8051 micro-controller. I got some 8051 dis-assemblers, and dis-assembled the code. It was really hard to follow, and looks like it was made that way. Luckily I found some datasheets for other Realtek eDP to LVDS converters. I found how the register are set-up, and was the info that I needed. However I search the ROM code, and couldn’t find the 1920x1080 resolution settings. I did find the sub-routine to program the registers, but couldn’t back track on where the info was coming from for the sub-routine.
After dumping the ROM, I tried to boot up the MB again, but the LCD was not working anymore. After doing some debugging, I found out that the 3.3V was not working. The Realtek 2136R drives the 3.3V, as it has some voltage regulators built into the chip. I am guessing when I hook up the Arduino Uno, and powered it with 3.3V, and it some how damaged the Realtek 2136R, by driving 3.3V into it. This was weird and really sucked. This was the third major problem.
I bought some Realtek RTD2136R from AliExpress. I have the soldering equipment and skills to switch it out. While waiting for the chips to get shipped from China to the USA, I came up with another plan. I saw that one of the Dell 3455 LCD panels had an EDID ROM. An EDID ROM has the info of the monitor or TV. New monitors and TVs have these ROMs, and allows the GPU to know what resolutions and timings are supported by the monitoTV. It also tells the GPU what the manufacture, model, build date, and some other info. You can google EDID ROM to find the info.
I flipped over the MB and probed some signals to see if it was looking for an EDID ROM. This is were I ran into my fourth problem. I think I pushed to hard on where the power connection was and blew out something on the power side. I switched out the main power diode, but that didn’t solve the problem. I did some debugging and didn’t find anything, as GND was connected to the main voltage input. With other things wrong, I just payed the $26 to get another MB.
When waiting for the new MB, I ordered some EDID ROMs and some ST 24C64 EEPROMs. I researched the EDID ROM info, and found some programs to help out. Also ROM files for different resolutions and timings. When I got the EDID ROM, I program it with a cheap 24/25 EEPROM readewriter now, so I didn’t have to use an Arduino anymore, as it might have been the problem too. I also solder in the wires to the 30pin LVDS breakout board, for the EDID ROM. It was ready, and just needed the new MB now.
Once I got the new MB, I hook things up, and it didn’t work with the external EDID ROM. The Dell 3455 MB doesn’t talk to an external EDID ROM. With that defeat, I almost gave up and bought the HDMI to LVDS converter. But before I did that, I went back to the Boot ROM one more time. I’m sure glad that I did that. Looking at the code, it ran from 0x0000 to 0x16C0. But there was info from 0x1F00 to 0x1F70 that I didn’t look at too much the first time. But since doing research on EDID ROMs, I saw it as EDID info now. EDID info is only 1,024bits in the first revs, but can go up to 2,048 bits in the latest revs. This matched the 0x80 address space for 1,024bits. Also, the first 8bytes (64bits) needs to be 0x00FFFFFFFFFFFF00 in the EDID specs. This matched the data in 0x1F00 to 0x1F07. I have found where they stored the resolution and timing info. Jackpot!
I copied the data over, and reformatted the data for the EDID program that I was using. I loaded into the program and it read it OK, as the data was rev1.4, and the program only read up to rev1.3. It display most of the data in rev1.3 format, which is not much different than rev1.4. It showed the resolution as 1920x1080 with a refresh at 60MHz. I was excited now, and work on what I have to change to get 1280x1024 resolution working with 60MHz. After doing some research, I changed the EDID data in the Boot ROM, and re-solder the Boot ROM back on to the MB. I excitedly hook things up and booted up the MB. Amazingly the Arcade1Up now was working during the BIOS boot up. But when Ubuntu 16 loaded up, the Arcade1Up LCD was losing sync. It worked for 1 sec, then flicked off for 3 sec, and then back on for 1 sec, and continued the cycling. It was basically working, just needed to fix the timing.
I de-solder the Boot ROM again, but I accidentally removed a 0201 resistor, along with the Boot ROM. I was stupidly using a hot air gun to remove the ROM, instead of Chipquick SMD remover. I accidentally hit the small resistor, as it is right next to the ROM. Of course it had to be the smallest f-ing resistor that is made, and was my fifth major problem. Luckily I had the first board, and I very carefully removed the resistor. I luckily got it re-solder onto the 2nd board. It was not on there good, but good enough. I re-programmed the Boot ROM with new EDID data. I then re-solder it back onto the board. When re-soldering it with the heat gun, it blew the small resistor away. I was being carefully, but not carefully enough, and I was pissed.
I gave up on the small resistor, and solder bodge wires on the resistor pads. I used polymide heat tape on the wires, to make sure they don’t move. I connected a through hole carbon resistor to the two bodges wires, fixing my mistake. Then I had a 150mil SOP8 socket. So I made 2x4pin Dupont wiring harness for the socket. Since 3 pins are grounded on the Boot ROM, I only had to solder 6 wires down on the Boot ROM pads of the MB. Then the 6 wires turned into two 4pin Dupont connectors, that connected right up to the 150mil SOP8 socket. Now I just took the socket to the computer, and plugged it in to the 24/25 EEPROM readewriter. After writing the Boot ROM, I then unlatch it from the EEPROM readewriter, and plugged into the MB, using the two 4pin Dupont connectors. This allowed me to quickly try things out, and after about 4-5 tries, I finally got the data right. To get things right is a little hard. There is an active area, and a blanking area. I will detail some of the details in the next paragraph. So if you don’t care about details, you can skip the next paragraph.
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Monitors are still using set-up from the CRT days. CRTs had an area before and after horizontal and vertical active area. This was called the (front) porch and deck (back porch). In this area is were it synced (vertically & horizontally) and found voltage average. This is basically how analog TV transmission worked, but had more stuff too and different, as it was analog. So for the Arcade1Up LCD, the active area is 1280x1024. The porch area is now called blanking area, and is controlled by the Data Enable (DE) bit, in the LVDS data. So when DE is high, it is in the active area, and when it is low, it is in the blanking area. For the vertical, there are 1024 active lines, and 39 blanking lines. So there is a total of 1063 vertical lines, but only 1024 lines are displayed. For the horizontal, there are 1280 pixels (pixel = g/b together) that are active, and 432 pixels are blank. So there is a total of 1712 pixels per line, where only 1280 are displayed. During the blanking area, there should be a vertical and horizontal sync. The vertical sync offset is 3, and width is 7. The horizontal sync offset is 80, and width is 136. But the syncs are pretty much ignored on LCDs, as LCDs don’t need it, as it is digital. So why the hell is there blanking area then? Simple answer is timing, which is clocking. There are 3 clocks needed, the vertical clock, horizontal clock, and pixel clock. These 3 clocks need to have gearing, and gearing for multiple resolutions. The blanking area helps to line up the 3 clocks for all resolutions. Lets look at the clocking of the Arcade1Up LCD, where the pixel clock is 109MHz, where a new pixel is set every rising edge. There are 1712 pixel per line (109,000,000/1712), making the horizontal clock 63.668kHz. There are 1063 vertical lines (63,668/1063), making the vertical clock 59.9Hz. Which is amazingly 60Hz refresh rate. So the blanking is needed to make the 3 clocks sync together. But it doesn’t end there, as the 30pin LVDS has 2 channels, meaning it sends 2 G/B 8-Bit pixels at the same time. So the pixel clock and horizontal info is cut in half. Pixel clock is now 54.5MHz, horizontal active area is 640, and blanking area is 216, with a total of 856. So the horizontal clock 63.668kHz is the same, making the refresh rate the same at 60Hz. I found out, only use the full numbers in the EDID ROM, so use the 109MHz pixel clock and so on. Now you know, and knowing is half the battle.
After getting the timing right in the EDID info in the Boot ROM, the LCD panel was now working in the boot and OS modes. So it was not blanking anymore in Ubuntu 16. I did it, and was able to change the resolution of the Dell AIO MB. Now I can change out the electronics in the Arcade1Up cabinet. I have bought new buttons and joysticks, with a USB connectors. This can easily plug into the USBs on the MB. I plan to just use the 500GB hard drive I am using now. It is my old PS4 HDD, where I switched out my PS4 with a 4TB SSD/HDD. I can also connect the RJ-45 ethernet to my 10G network. Then just put all the data on my NAS system. I have ~20TB free on my NAS. Or I can just get the wifi card for the MB.
To skip boot up, go to 1:50
After getting the LCD working, I went into the BIOS, and found that the BIOS was in manufacture mode. It was asking for a service number or something like that. I didn’t record any info. I found to get out of manufacture mode, is go to the last page of the BIOS. Then pick the restore values, or something like that. I did that, and re-booted, and was in normal mode now. But the asset, model, and service numbers are all blank now. So, if you do this, please copy all these numbers in BIOS, before changing the Boot ROM for the RTD2136R (eDP to LVDS converter).
I ran into my sixth problem. When booting into the BIOS of the new board, I saw the APU was an AMD E2-7110. The company sent me the wrong board. But since I hacked up the board, I cannot send it back. The AMD E2-7110 APU is a lot more weaker than the A8-7410. The 4 CPU ran at 1.8GHz, and the GFX ran at 600MHz. Hopefully this is the last kick in the nuts for this project. After thinking about it, I got another board, and this time I checked the APU before hacking it. I plan on selling the E2-7110 board. If anyone wants it, let me know. I will leave on the Boot ROM stuff on it. Plus give two Boot ROMs, one for 1280x1024, and other is the original 1920x1080. The board also has bodge wires attached to a resistor, as I detailed earlier.
Conclusion:
So, how much did this cost? All pricing is the total, and includes shipping.
Must Haves:
Dell Inspiron 3455 MB with A8-7410: $26.04
Dell Inspiron 3455 Heatsink & Fan: $7.64
Dell Power Supply $20.68 – F-you Dell
Used 4GB DDR3L 1600 SO-DIMM $9.34
30pin FFC/FPC Breakout board $4.12 – can get a lot cheaper
30pin 1mm FFC/FPC 200mm $4.53 – can get a lot cheaper
500GB HDD $0 (already had, can use HDD/SD/USB Drive)
Total: $72.35
Nice to Haves:
Dell Inspiron 3455 Backlight Cable $6.00 – Need to ground pin to boot if don’t have wire
Dell Inspiron 3455 Power Button Cable $4.20
Dell Inspiron 3455 O/HDD & Power $7.99 – Mine was broken F-u Murphy
Total: $ 18.19 + $72.35 = $90.54
You can get a lot cheaper LVDS cables from China, using AliExpress. Then you don’t need to solder, and save time. The end that connects to the LCD panel is a FI-X30HL connector. Basically a connector that goes over the FFC cable. Other end is a 30pin 1mm pitch FFC to connect to the MB. Then you can make it as long as needed, like 10inches (254mm).
For the MB to Boot, a backlight cable is needed, since it selects what LCD is being used. If you don’t have it, then 1 or 2 pins need grounding on the pinout, for the MB to boot to BIOS.
Also, the power cable for the HDD only supplies 5V, so if using, make sure HDD only needs 5V, usually a laptop HDD. Or you have to attached the other voltages. The HDD uses a SATA data cable to connect to the MB and HDD. The optical drive, uses a SATA data cable too.
Price for Raspberry PI 3 B+
Raspberry Pi 3 $34.30
Power Supply $9.99 to $11.99
HDMI to LVDS $26.99
HDMI Cable $6.99 (I included LVDS cable in other)
SD Card $0 (Have extra one, like I had HDD)
Total: $79.27
Nice to Haves:
RP3 Case $5-$12
Heatsinks $3
Total: $8 + 79.27 = $87.27
All in all, it is roughly the same price for each of the setup, and sometimes the AIO MB can be a little cheaper. The numbers can be changed a lot, depending on what you get. I spent the extra money, and got the cables, but then the powesignal cable for HDD didn’t work, my seventh problem. Also, do you get a case or not for the Raspberry Pi 3. Then Raspberry Pi 4 is more expense, and has fixed RAM. I can spend another $10, and double my RAM to 8GB. Cannot do that on the Raspberry Pi 4, and maxed out at 4GB. But Raspberry Pi 4 has DDR4 2100, compared to DDR3L-1600. But I know the difference in speed doesn’t matter that much,
Also, it comes down to preference. Do you want to be on ARM architecture. Where there is good support for RetroPie. Or do you want to be on x86, where you can do RetroPie, and many more things, as x86 has a lot more support than ARM right now. But x86 takes a little more to set-up for RetroPie, but not too much from reading. I have gotten that far, so cannot say.
So, AIO computers are good choices, if you want to put the work into it. It is not as straight forward as the Raspberry Pi, but it is a lot more powerful. I guess power comes at a price, and responsibility said by some spider super hero.
Also, if you plan to upgrade the monitor already, it might be a better solution. As you can use the monitor that comes with the AIO MB. Then you don’t have to worry about changing the resolution, plus, you can change the brightness too, as many AIO had this feature built in. I saw many different sizes and choices when looking for an AIO MB. So if you are switching out the monitor already, then this might be a great and probably cheaper solution. Also, it might be better to get the whole AIO computer then, then to piece it out. Also, a lot of AIO had touch screen, which could help out. The Dell Inspiron 3455 has a touch screen. So if I went to that monitor, and got the control board, I could enable the touch screen.
Note:
I have only done this work on the Dell Inspiron 3455 MB. I am assuming a lot of the other AIO set-ups are very familiar. But I cannot guarantee it of course, as this is the nature of hacking. First advice it to figure out what is used to convert the video to the LVDS signal. Most likely a Realtek chip. If you can find the chip in the picture of the MB, then hopefully you can see a EEPROM next to it. If there is a EEPROM next to it, then there is a great chance you can change the resolution. And knowing the industry, the 8051 Boot ROM code is probably the same or very close to what I found. As I bet Realtek gives this code to Dell and other companies. It makes sense to just use the EDID info. So if you want to use an outside EDID, then it is easy to do.
Edit 1: Added in stereo speaker info to MB part. Also updated RP3 pricing.
submitted by VonDoomLab to Arcade1Up [link] [comments] Looking at the Raspberry Pi option, it’s major weak point is the HDMI to LVDS converter, which costs $30. I know that there are some computers that have a LVDS hook-up, but there are many different kinds. After looking around, I found the ALL In One (AIO) computers. These are low cost computers that are built into the monitor. So the motherboard, HDD, and optical drive are all behind the LCD display. The motherboard connects to the LCD, with a LVDS connection. There is also a backlight circuit to drive the LEDs chains, sometimes on the motherboard. This looked like a great option, and turned out to be one, after some hard work.
I went onto eBay and searched for some AIO motherboards, and the prices varied. However, there are some great boards that I found that were in the $20s to $30s range, which had low cost APUs. I finally decided on a Dell Inspiron 3455 motherboard, with an AMD A8-7410 APU. The processor is a mobile processor that Dell put into an AIO computers. It is based on the Carrizo-L, and is 28nm. It has 4 cores running at 2.2Ghz-2.5GHz, with 2MB of level2 cache. One channel of DDR3L, where up to 2GB can be shared with the GFX. The attached GPU is the Radeon R5, with 128 cores running at 300MHz-850MHz. It has a RJ-45 port, 2 x USB2, 2 x USB3, audio in, audio out, HDMI out, memory card reader, and a wifi port connection. The board was new, and I got it shipped for $26.04. The AMD APU is by far a lot more powerful than the Raspberry Pi 3 APU and must likely the Raspberry Pi 4 APU too.
Edit: Forgot to mention that the Dell AIO MB has 2x15w stereo speaker connections. Now I don't have to worry about the mono audio on the SF2.
Before buying the board, I did do some research. The first thing I researched was what monitor(s) did it come with. There are 3 different 24” 1920x1080 LCD monitors that came with this AIO computer. A lot different than the 17” 1280x1024 LCD that came with the Arcade1Up, but I will get to that later. I pulled up the datasheet for one of the monitors, and found it used the same 30 pin LVDS as the Arcade1up monitor. Since it had the same pin-out, I should be able to get it working. I had to find a solution to change the resolution, which I did. I will detail this later. Also, the motherboard has an HDMI output. So if I couldn’t get the LVDS working, I could buy the HDMI to LVDS converter.
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I got some DDR3L SO-DIMM memory, cheap power supply, heatsink, and some Dell 3455 cables. I hooked things up, and connected the HDMI out to a monitor. I powered it up, and ran into my first problem. Dell is now pulling an Apple. Dell doesn’t want people to use cheap 3rd party power supplies, as they only want people to use their overpriced cheaply made power supply. I found out that Dell now puts a lock out chip into their power supplies. I had to buy another power supply. I found out that people have cracked this lockout, but the Dell power supplies were about the same price. More expensive then a regular power supply though. This was the first major problem I ran into.
The first part I looked at was the backlight driver, that was on the MB. Two of the three LCD panels have 3 LED chains, while the last LCD panel have 4 LED chains. After doing some research I saw that they control this by the wire used to connect the backlight to the MB. If 3 LED chains, then 2 pins were grounded on wire, and 4 LED chains, then 1 pin was grounded. So there are 2 different cables to connect the back light to the MB, made by Dell. Since the monitor in the Arcade1Up, has 4 LED chains, I needed to ground one pin. Also I found out that you need to use the cable, or ground 1 or 2 pins. If not, then the MB will not boot, and give you a monitor error.
But in the end, it didn’t matter. If you read my other post, you would know that the LED chains in the Arcade1Up LCD panel need a low voltage with a buck circuit, where this driver drove high voltage, using a boost circuit. So I decided to use the backlight driver that came with the Arcade1Up, but modified to make it dimmable. This info is in my last post. The backlight driver chip was an OCR554 chip, and I couldn’t get/find the datasheet, even after emailing the manufacture. This was the second problem, but not that big. I stopped working on the backlight and switched my intention to the LCD resolution.
Link to my Last Reddit Post
I first decided to figure out how to connect the LCD to the MB. I used the original LVDS cable and cut the wires going into the 2x15 connector, on the Arcade1Up board side. I then soldered the wires into a 30pin 0.5mm & 1mm pitch flat wire breakout board. Then used a 1mm pitch 30pin FFC wire to connect the breakout board to the MB. This worked out great, and gave me the extra length I needed. If people need, I can post the pin out of the 2x15 connector.
Now with the MB connected to the LCD, and the backlight driver connected too, I tried booting it. Of course, this failed, and the LCD just kept on trying to sync to the wrong resolution. I began to try to think how to change the resolution. I began to look at the LVDS connection. I knew it used a Realtek eDP to LVDS chip, before buying the MB. I could see it in the pictures of the eBay sale. I also saw the EEPROM next to the converter. This was my first idea of attack. When I got the board, I found out it was a Realtek RTD2136R eDP to LVDS converter, using a ST 24C64WR EEPROM, as the Boot ROM.
I used a Arduino Uno to download the Boot ROM. I couldn’t find or get the Realtek RTD2136R datasheet. It is controlled by Realtek and manufactures. After doing some research, I found out that the chip uses an old 8051 micro-controller. I got some 8051 dis-assemblers, and dis-assembled the code. It was really hard to follow, and looks like it was made that way. Luckily I found some datasheets for other Realtek eDP to LVDS converters. I found how the register are set-up, and was the info that I needed. However I search the ROM code, and couldn’t find the 1920x1080 resolution settings. I did find the sub-routine to program the registers, but couldn’t back track on where the info was coming from for the sub-routine.
After dumping the ROM, I tried to boot up the MB again, but the LCD was not working anymore. After doing some debugging, I found out that the 3.3V was not working. The Realtek 2136R drives the 3.3V, as it has some voltage regulators built into the chip. I am guessing when I hook up the Arduino Uno, and powered it with 3.3V, and it some how damaged the Realtek 2136R, by driving 3.3V into it. This was weird and really sucked. This was the third major problem.
I bought some Realtek RTD2136R from AliExpress. I have the soldering equipment and skills to switch it out. While waiting for the chips to get shipped from China to the USA, I came up with another plan. I saw that one of the Dell 3455 LCD panels had an EDID ROM. An EDID ROM has the info of the monitor or TV. New monitors and TVs have these ROMs, and allows the GPU to know what resolutions and timings are supported by the monitoTV. It also tells the GPU what the manufacture, model, build date, and some other info. You can google EDID ROM to find the info.
I flipped over the MB and probed some signals to see if it was looking for an EDID ROM. This is were I ran into my fourth problem. I think I pushed to hard on where the power connection was and blew out something on the power side. I switched out the main power diode, but that didn’t solve the problem. I did some debugging and didn’t find anything, as GND was connected to the main voltage input. With other things wrong, I just payed the $26 to get another MB.
When waiting for the new MB, I ordered some EDID ROMs and some ST 24C64 EEPROMs. I researched the EDID ROM info, and found some programs to help out. Also ROM files for different resolutions and timings. When I got the EDID ROM, I program it with a cheap 24/25 EEPROM readewriter now, so I didn’t have to use an Arduino anymore, as it might have been the problem too. I also solder in the wires to the 30pin LVDS breakout board, for the EDID ROM. It was ready, and just needed the new MB now.
Once I got the new MB, I hook things up, and it didn’t work with the external EDID ROM. The Dell 3455 MB doesn’t talk to an external EDID ROM. With that defeat, I almost gave up and bought the HDMI to LVDS converter. But before I did that, I went back to the Boot ROM one more time. I’m sure glad that I did that. Looking at the code, it ran from 0x0000 to 0x16C0. But there was info from 0x1F00 to 0x1F70 that I didn’t look at too much the first time. But since doing research on EDID ROMs, I saw it as EDID info now. EDID info is only 1,024bits in the first revs, but can go up to 2,048 bits in the latest revs. This matched the 0x80 address space for 1,024bits. Also, the first 8bytes (64bits) needs to be 0x00FFFFFFFFFFFF00 in the EDID specs. This matched the data in 0x1F00 to 0x1F07. I have found where they stored the resolution and timing info. Jackpot!
I copied the data over, and reformatted the data for the EDID program that I was using. I loaded into the program and it read it OK, as the data was rev1.4, and the program only read up to rev1.3. It display most of the data in rev1.3 format, which is not much different than rev1.4. It showed the resolution as 1920x1080 with a refresh at 60MHz. I was excited now, and work on what I have to change to get 1280x1024 resolution working with 60MHz. After doing some research, I changed the EDID data in the Boot ROM, and re-solder the Boot ROM back on to the MB. I excitedly hook things up and booted up the MB. Amazingly the Arcade1Up now was working during the BIOS boot up. But when Ubuntu 16 loaded up, the Arcade1Up LCD was losing sync. It worked for 1 sec, then flicked off for 3 sec, and then back on for 1 sec, and continued the cycling. It was basically working, just needed to fix the timing.
I de-solder the Boot ROM again, but I accidentally removed a 0201 resistor, along with the Boot ROM. I was stupidly using a hot air gun to remove the ROM, instead of Chipquick SMD remover. I accidentally hit the small resistor, as it is right next to the ROM. Of course it had to be the smallest f-ing resistor that is made, and was my fifth major problem. Luckily I had the first board, and I very carefully removed the resistor. I luckily got it re-solder onto the 2nd board. It was not on there good, but good enough. I re-programmed the Boot ROM with new EDID data. I then re-solder it back onto the board. When re-soldering it with the heat gun, it blew the small resistor away. I was being carefully, but not carefully enough, and I was pissed.
I gave up on the small resistor, and solder bodge wires on the resistor pads. I used polymide heat tape on the wires, to make sure they don’t move. I connected a through hole carbon resistor to the two bodges wires, fixing my mistake. Then I had a 150mil SOP8 socket. So I made 2x4pin Dupont wiring harness for the socket. Since 3 pins are grounded on the Boot ROM, I only had to solder 6 wires down on the Boot ROM pads of the MB. Then the 6 wires turned into two 4pin Dupont connectors, that connected right up to the 150mil SOP8 socket. Now I just took the socket to the computer, and plugged it in to the 24/25 EEPROM readewriter. After writing the Boot ROM, I then unlatch it from the EEPROM readewriter, and plugged into the MB, using the two 4pin Dupont connectors. This allowed me to quickly try things out, and after about 4-5 tries, I finally got the data right. To get things right is a little hard. There is an active area, and a blanking area. I will detail some of the details in the next paragraph. So if you don’t care about details, you can skip the next paragraph.
https://preview.redd.it/4duzgj84arh31.jpg?width=2268&format=pjpg&auto=webp&s=fe1650fcc651806a46326a06709835616897e65f
https://preview.redd.it/g1ikb926arh31.jpg?width=2268&format=pjpg&auto=webp&s=17365b3379cb03b12b0ed3961d97ee19918fa4d8
https://preview.redd.it/yvgd629carh31.jpg?width=2268&format=pjpg&auto=webp&s=102bcfb9bde80eb5d6fb21eb89ce35db641685b1
https://preview.redd.it/rdfogcsdarh31.jpg?width=2268&format=pjpg&auto=webp&s=fd94520a0a9689b231b415d98c94fed7b9501c3b
Monitors are still using set-up from the CRT days. CRTs had an area before and after horizontal and vertical active area. This was called the (front) porch and deck (back porch). In this area is were it synced (vertically & horizontally) and found voltage average. This is basically how analog TV transmission worked, but had more stuff too and different, as it was analog. So for the Arcade1Up LCD, the active area is 1280x1024. The porch area is now called blanking area, and is controlled by the Data Enable (DE) bit, in the LVDS data. So when DE is high, it is in the active area, and when it is low, it is in the blanking area. For the vertical, there are 1024 active lines, and 39 blanking lines. So there is a total of 1063 vertical lines, but only 1024 lines are displayed. For the horizontal, there are 1280 pixels (pixel = g/b together) that are active, and 432 pixels are blank. So there is a total of 1712 pixels per line, where only 1280 are displayed. During the blanking area, there should be a vertical and horizontal sync. The vertical sync offset is 3, and width is 7. The horizontal sync offset is 80, and width is 136. But the syncs are pretty much ignored on LCDs, as LCDs don’t need it, as it is digital. So why the hell is there blanking area then? Simple answer is timing, which is clocking. There are 3 clocks needed, the vertical clock, horizontal clock, and pixel clock. These 3 clocks need to have gearing, and gearing for multiple resolutions. The blanking area helps to line up the 3 clocks for all resolutions. Lets look at the clocking of the Arcade1Up LCD, where the pixel clock is 109MHz, where a new pixel is set every rising edge. There are 1712 pixel per line (109,000,000/1712), making the horizontal clock 63.668kHz. There are 1063 vertical lines (63,668/1063), making the vertical clock 59.9Hz. Which is amazingly 60Hz refresh rate. So the blanking is needed to make the 3 clocks sync together. But it doesn’t end there, as the 30pin LVDS has 2 channels, meaning it sends 2 G/B 8-Bit pixels at the same time. So the pixel clock and horizontal info is cut in half. Pixel clock is now 54.5MHz, horizontal active area is 640, and blanking area is 216, with a total of 856. So the horizontal clock 63.668kHz is the same, making the refresh rate the same at 60Hz. I found out, only use the full numbers in the EDID ROM, so use the 109MHz pixel clock and so on. Now you know, and knowing is half the battle.
After getting the timing right in the EDID info in the Boot ROM, the LCD panel was now working in the boot and OS modes. So it was not blanking anymore in Ubuntu 16. I did it, and was able to change the resolution of the Dell AIO MB. Now I can change out the electronics in the Arcade1Up cabinet. I have bought new buttons and joysticks, with a USB connectors. This can easily plug into the USBs on the MB. I plan to just use the 500GB hard drive I am using now. It is my old PS4 HDD, where I switched out my PS4 with a 4TB SSD/HDD. I can also connect the RJ-45 ethernet to my 10G network. Then just put all the data on my NAS system. I have ~20TB free on my NAS. Or I can just get the wifi card for the MB.
To skip boot up, go to 1:50
After getting the LCD working, I went into the BIOS, and found that the BIOS was in manufacture mode. It was asking for a service number or something like that. I didn’t record any info. I found to get out of manufacture mode, is go to the last page of the BIOS. Then pick the restore values, or something like that. I did that, and re-booted, and was in normal mode now. But the asset, model, and service numbers are all blank now. So, if you do this, please copy all these numbers in BIOS, before changing the Boot ROM for the RTD2136R (eDP to LVDS converter).
I ran into my sixth problem. When booting into the BIOS of the new board, I saw the APU was an AMD E2-7110. The company sent me the wrong board. But since I hacked up the board, I cannot send it back. The AMD E2-7110 APU is a lot more weaker than the A8-7410. The 4 CPU ran at 1.8GHz, and the GFX ran at 600MHz. Hopefully this is the last kick in the nuts for this project. After thinking about it, I got another board, and this time I checked the APU before hacking it. I plan on selling the E2-7110 board. If anyone wants it, let me know. I will leave on the Boot ROM stuff on it. Plus give two Boot ROMs, one for 1280x1024, and other is the original 1920x1080. The board also has bodge wires attached to a resistor, as I detailed earlier.
Conclusion:
So, how much did this cost? All pricing is the total, and includes shipping.
Must Haves:
Dell Inspiron 3455 MB with A8-7410: $26.04
Dell Inspiron 3455 Heatsink & Fan: $7.64
Dell Power Supply $20.68 – F-you Dell
Used 4GB DDR3L 1600 SO-DIMM $9.34
30pin FFC/FPC Breakout board $4.12 – can get a lot cheaper
30pin 1mm FFC/FPC 200mm $4.53 – can get a lot cheaper
500GB HDD $0 (already had, can use HDD/SD/USB Drive)
Total: $72.35
Nice to Haves:
Dell Inspiron 3455 Backlight Cable $6.00 – Need to ground pin to boot if don’t have wire
Dell Inspiron 3455 Power Button Cable $4.20
Dell Inspiron 3455 O/HDD & Power $7.99 – Mine was broken F-u Murphy
Total: $ 18.19 + $72.35 = $90.54
You can get a lot cheaper LVDS cables from China, using AliExpress. Then you don’t need to solder, and save time. The end that connects to the LCD panel is a FI-X30HL connector. Basically a connector that goes over the FFC cable. Other end is a 30pin 1mm pitch FFC to connect to the MB. Then you can make it as long as needed, like 10inches (254mm).
For the MB to Boot, a backlight cable is needed, since it selects what LCD is being used. If you don’t have it, then 1 or 2 pins need grounding on the pinout, for the MB to boot to BIOS.
Also, the power cable for the HDD only supplies 5V, so if using, make sure HDD only needs 5V, usually a laptop HDD. Or you have to attached the other voltages. The HDD uses a SATA data cable to connect to the MB and HDD. The optical drive, uses a SATA data cable too.
Price for Raspberry PI 3 B+
Raspberry Pi 3 $34.30
Power Supply $9.99 to $11.99
HDMI to LVDS $26.99
HDMI Cable $6.99 (I included LVDS cable in other)
SD Card $0 (Have extra one, like I had HDD)
Total: $79.27
Nice to Haves:
RP3 Case $5-$12
Heatsinks $3
Total: $8 + 79.27 = $87.27
All in all, it is roughly the same price for each of the setup, and sometimes the AIO MB can be a little cheaper. The numbers can be changed a lot, depending on what you get. I spent the extra money, and got the cables, but then the powesignal cable for HDD didn’t work, my seventh problem. Also, do you get a case or not for the Raspberry Pi 3. Then Raspberry Pi 4 is more expense, and has fixed RAM. I can spend another $10, and double my RAM to 8GB. Cannot do that on the Raspberry Pi 4, and maxed out at 4GB. But Raspberry Pi 4 has DDR4 2100, compared to DDR3L-1600. But I know the difference in speed doesn’t matter that much,
Also, it comes down to preference. Do you want to be on ARM architecture. Where there is good support for RetroPie. Or do you want to be on x86, where you can do RetroPie, and many more things, as x86 has a lot more support than ARM right now. But x86 takes a little more to set-up for RetroPie, but not too much from reading. I have gotten that far, so cannot say.
So, AIO computers are good choices, if you want to put the work into it. It is not as straight forward as the Raspberry Pi, but it is a lot more powerful. I guess power comes at a price, and responsibility said by some spider super hero.
Also, if you plan to upgrade the monitor already, it might be a better solution. As you can use the monitor that comes with the AIO MB. Then you don’t have to worry about changing the resolution, plus, you can change the brightness too, as many AIO had this feature built in. I saw many different sizes and choices when looking for an AIO MB. So if you are switching out the monitor already, then this might be a great and probably cheaper solution. Also, it might be better to get the whole AIO computer then, then to piece it out. Also, a lot of AIO had touch screen, which could help out. The Dell Inspiron 3455 has a touch screen. So if I went to that monitor, and got the control board, I could enable the touch screen.
Note:
I have only done this work on the Dell Inspiron 3455 MB. I am assuming a lot of the other AIO set-ups are very familiar. But I cannot guarantee it of course, as this is the nature of hacking. First advice it to figure out what is used to convert the video to the LVDS signal. Most likely a Realtek chip. If you can find the chip in the picture of the MB, then hopefully you can see a EEPROM next to it. If there is a EEPROM next to it, then there is a great chance you can change the resolution. And knowing the industry, the 8051 Boot ROM code is probably the same or very close to what I found. As I bet Realtek gives this code to Dell and other companies. It makes sense to just use the EDID info. So if you want to use an outside EDID, then it is easy to do.
Edit 1: Added in stereo speaker info to MB part. Also updated RP3 pricing.
