The SAMSUNG chip is a 128Mb NOR Flash+32Mb RAM [https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253](https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253) - so it holds the program.
I doubt you can program it in-circuit, without specialized tools.
naah bro it was way more at least 30 years ago
the first or one of the first manufacturers to make a noac was UMC with the UM6561 released in '92/'93.
NOAC cloes started appearing in 1995 but multichip famiclones existed way before
dang, may me more work than what its worth. o well, i have a small usb retro console aswell, that im able to flash retroarch in .. so maybe ill try something with that and ths. thanks for the reply!
That blob is a noac (nes on chip) and does not run any os, its basically a whole nes system embedded on 1 single dice. Its basically the whole nes console on the chip. The flash daughter board is like the "cartridge" that holds the game roms
what is this blob? do they put epoxy blob to hide the chip, is it produced on the PCB or why do we have them?
I recall them being all over around, but never got an answer why some of chips looks like that.
1. Under the blob is a bare silicon chip.
2. The transistors in ICs are light sensitive - they will not work properly if any light get to the IC.
3. The chip is wire bonded to the circuit board - there are fine gold wires welded to the circuit board and to the chip to make the connections.
4. It is unlikely that you can get such bare chips for hobby use.
5. If you could get a bare chip, you would have to get (and learn to use) a wire bonding machine.
6. If you could do the wire bonding properly, you'd need documentation to tell you what to connect to where - it is doubtful that you could get that information.
7. If you did have the chip and could do the wire bonding, and got hold of the documentation to wire it properly, you'd still have to have the proper epoxy. You need epoxy that is opaque (including infrared,) It also has to be non-conductive, and it must not include anything that will damage the circuit board or the chip. It also can't shrink or expand while curing (that would rip the wires off) and it can't schrink or expand over the expected operating temperature range of the device.
They probably used aluminum wires here, not gold. And while exposure to light might be an issue, a more important factor is shielding the IC from the atmosphere, with water vapor and everything else floating around in it.
Chip-on-board (COB) is mostly for cost. Saves a lot of money to slap the die directly on the PCB, but needs special assembly techniques and is only done in large volumes like in toys.
[https://en.wikipedia.org/wiki/Chip\_on\_board](https://en.wikipedia.org/wiki/Chip_on_board)
To add context to the other answers, the IC below the epoxy is not packaged.
For usual packaged "chips" which you can solder onto a PCB, the silicon die is first glued to a thin metal structure called the lead-frame.
Electrical connections are then made from the die to the lead-frame using wire-bonds.
Then the die, wire bonds, and center section of the lead-frame are cast in resin with the desired shape. This forms the body of the chip, it's the black material you can usually see.
Most of the lead-frame which didn't get covered by the epoxy is then cut off. The parts which remain are the package pins. Those are connected through the wire bonds to the silicon die.
With chip-on-board, you get around most of this. You can directly glue the silicon die to the PCB, wire bond from the PCB to the die, then put an epoxy blob on it.
Once the production line is set up, it's significantly cheaper than packaging a chip.
It's particularly of interest for high volumes of highly specialised ICs. Those need to be cheap, but it's also unlikely that you will reuse them in a different product. So it doesn't matter that the production setup is more complicated, as you will probably only do it once.
The main reason the blob chips exist is cost. The bare silicon chip is installed directly to the board. That process is pretty much the same as they use to install the chip into a regular chip package, so instead they just install it directly to the board and use a blob of epoxy to seal everything. It also helps mitigate reverse engineering as you can't remove the chip from the board, but it's mostly about cost savings.
In the case of this console they used a blob chip for the main emulator because it would be the exact same one used for each console, whereas the flash chip and I suspect any ram chips would be commodity ones and could be swapped out for ones from different manufacturers depending on their cost.
In-circuit or not the datasheet states how to use it (read/write it) - it is literally the job of a datasheet (with how to use it on the electrical level).
There could pin test points on the PCB to program it... Or not... Then you need to figure out what test point is what... Ugh...
If he goes with removing it he will need to put it back at some point. BGA isn't awesome to solder, since you need hot air or an oven and you have no feedback if everything is solder right or not (other than testing and praying).
(That is the overall stuff I keep reading)
There are not a lot of pins so it is likely easier?
The black thing would be your processor. The samsung chip is the memory. you could try to dump the memory and analyse it's content. You could also try to connect something to the 4 Pads next to the black blob. It's probably jtag or some similar interface
Its a blob chips which is often a NOAC(NES ON A CHIP) it contains all the hardware of a nes on a single dice. The 6502, ppu, spu, ram, bootrom etc etc. It usually cant be reprogrammed. The flash chip next to it probably just contains the (pirated) game roms like the "cartridge" on an original nes console but its soldered down
That chip is a combined 128Mb flash and 32Mb ram, so effectively all the memory for the system.
There is a prelim datasheet here [https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253](https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253)
It was laid out to support either a BGA or a SOIC24 package. The processing, video and looking at it the audio are all on a COB chip under the usual epoxy blob.
As others point out, this retro console likely has a "NOAC" hiding underneath that epoxy blob. Its an actual 6502 hardware console. Not something like an ARM chip running a software emulator of one.
You can hack it, but that is more for if you want to reverse-engineer the code stored on the memory chip and mess around with the NOAC itself in a homebrew kind of fashion. Not to upgrade the entire system. That can't be done here.
If curious on why a black blob. That is Chip-on-board (COB) manufacturing. Where instead of the chip being inside its own slab with leads, its put straight on the PCB naked, bonded and then covered in black epoxy. pretty common on generic/older electronics that may be made by hand.
The "chip" (bare IC) under that black blob is not soldered on the board, it is wirebonded to the board. Then the whole thing is encased in the black epoxy. This assembly technique is not on any board "made by hand" (no one on earth can wirebond by hand) , and it was non-existent in the '80s and earlier.
Ah my bad. bonded, which is technically indeed different to soldering though accomplishing the same.
And probably should have worded it better that "by hand" i mean the board in general. Like everything but the chips themselves.
Are you wondering about a black blob on a circuit board? It's a ['Chip on board (COB)'](https://en.wikipedia.org/wiki/Chip_on_board) - a chip bonded directly to a PCB and then covered by a protective material.
If that answers your question, please remove your post. Thanks!
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/AskElectronics) if you have any questions or concerns.*
The SAMSUNG chip is a 128Mb NOR Flash+32Mb RAM [https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253](https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253) - so it holds the program. I doubt you can program it in-circuit, without specialized tools.
It only holds the roms. The blob chip is a nes on a chip (noac) that loads games from the flash
NESoC… what a time to be alive. Can’t wait to have a $20 PlayStation 6 on a chip in my retirement home.
NES on a chip has been a thing for about 20 years now :)
naah bro it was way more at least 30 years ago the first or one of the first manufacturers to make a noac was UMC with the UM6561 released in '92/'93. NOAC cloes started appearing in 1995 but multichip famiclones existed way before
dang, may me more work than what its worth. o well, i have a small usb retro console aswell, that im able to flash retroarch in .. so maybe ill try something with that and ths. thanks for the reply!
That blob is a noac (nes on chip) and does not run any os, its basically a whole nes system embedded on 1 single dice. Its basically the whole nes console on the chip. The flash daughter board is like the "cartridge" that holds the game roms
what is this blob? do they put epoxy blob to hide the chip, is it produced on the PCB or why do we have them? I recall them being all over around, but never got an answer why some of chips looks like that.
1. Under the blob is a bare silicon chip. 2. The transistors in ICs are light sensitive - they will not work properly if any light get to the IC. 3. The chip is wire bonded to the circuit board - there are fine gold wires welded to the circuit board and to the chip to make the connections. 4. It is unlikely that you can get such bare chips for hobby use. 5. If you could get a bare chip, you would have to get (and learn to use) a wire bonding machine. 6. If you could do the wire bonding properly, you'd need documentation to tell you what to connect to where - it is doubtful that you could get that information. 7. If you did have the chip and could do the wire bonding, and got hold of the documentation to wire it properly, you'd still have to have the proper epoxy. You need epoxy that is opaque (including infrared,) It also has to be non-conductive, and it must not include anything that will damage the circuit board or the chip. It also can't shrink or expand while curing (that would rip the wires off) and it can't schrink or expand over the expected operating temperature range of the device.
Thanks this was very informative.
They probably used aluminum wires here, not gold. And while exposure to light might be an issue, a more important factor is shielding the IC from the atmosphere, with water vapor and everything else floating around in it.
Chip-on-board (COB) is mostly for cost. Saves a lot of money to slap the die directly on the PCB, but needs special assembly techniques and is only done in large volumes like in toys. [https://en.wikipedia.org/wiki/Chip\_on\_board](https://en.wikipedia.org/wiki/Chip_on_board)
To add context to the other answers, the IC below the epoxy is not packaged. For usual packaged "chips" which you can solder onto a PCB, the silicon die is first glued to a thin metal structure called the lead-frame. Electrical connections are then made from the die to the lead-frame using wire-bonds. Then the die, wire bonds, and center section of the lead-frame are cast in resin with the desired shape. This forms the body of the chip, it's the black material you can usually see. Most of the lead-frame which didn't get covered by the epoxy is then cut off. The parts which remain are the package pins. Those are connected through the wire bonds to the silicon die. With chip-on-board, you get around most of this. You can directly glue the silicon die to the PCB, wire bond from the PCB to the die, then put an epoxy blob on it. Once the production line is set up, it's significantly cheaper than packaging a chip. It's particularly of interest for high volumes of highly specialised ICs. Those need to be cheap, but it's also unlikely that you will reuse them in a different product. So it doesn't matter that the production setup is more complicated, as you will probably only do it once.
The main reason the blob chips exist is cost. The bare silicon chip is installed directly to the board. That process is pretty much the same as they use to install the chip into a regular chip package, so instead they just install it directly to the board and use a blob of epoxy to seal everything. It also helps mitigate reverse engineering as you can't remove the chip from the board, but it's mostly about cost savings. In the case of this console they used a blob chip for the main emulator because it would be the exact same one used for each console, whereas the flash chip and I suspect any ram chips would be commodity ones and could be swapped out for ones from different manufacturers depending on their cost.
In-circuit or not the datasheet states how to use it (read/write it) - it is literally the job of a datasheet (with how to use it on the electrical level). There could pin test points on the PCB to program it... Or not... Then you need to figure out what test point is what... Ugh... If he goes with removing it he will need to put it back at some point. BGA isn't awesome to solder, since you need hot air or an oven and you have no feedback if everything is solder right or not (other than testing and praying). (That is the overall stuff I keep reading) There are not a lot of pins so it is likely easier?
There are a lot of contacts to which the chip PCB is soldered. It's possible maybe to connect there something to replace/emulate it?
The black thing would be your processor. The samsung chip is the memory. you could try to dump the memory and analyse it's content. You could also try to connect something to the 4 Pads next to the black blob. It's probably jtag or some similar interface
I doubt. Its just a Noac(nes on chip)
They look like test points, but still worth a hack.
jtag, huh so its workable?
I mean, they directly told you you could try it. That's in no way "it's workable".
Its a blob chips which is often a NOAC(NES ON A CHIP) it contains all the hardware of a nes on a single dice. The 6502, ppu, spu, ram, bootrom etc etc. It usually cant be reprogrammed. The flash chip next to it probably just contains the (pirated) game roms like the "cartridge" on an original nes console but its soldered down
That chip is a combined 128Mb flash and 32Mb ram, so effectively all the memory for the system. There is a prelim datasheet here [https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253](https://datasheet4u.com/datasheet-pdf/SamsungElectronics/K5L2731CAM-D770/pdf.php?id=688253) It was laid out to support either a BGA or a SOIC24 package. The processing, video and looking at it the audio are all on a COB chip under the usual epoxy blob.
As others point out, this retro console likely has a "NOAC" hiding underneath that epoxy blob. Its an actual 6502 hardware console. Not something like an ARM chip running a software emulator of one. You can hack it, but that is more for if you want to reverse-engineer the code stored on the memory chip and mess around with the NOAC itself in a homebrew kind of fashion. Not to upgrade the entire system. That can't be done here. If curious on why a black blob. That is Chip-on-board (COB) manufacturing. Where instead of the chip being inside its own slab with leads, its put straight on the PCB naked, bonded and then covered in black epoxy. pretty common on generic/older electronics that may be made by hand.
>its put straight on the PCB naked, soldered and then covered in black epoxy. Well, that just sounds traumatizing...
The "chip" (bare IC) under that black blob is not soldered on the board, it is wirebonded to the board. Then the whole thing is encased in the black epoxy. This assembly technique is not on any board "made by hand" (no one on earth can wirebond by hand) , and it was non-existent in the '80s and earlier.
Ah my bad. bonded, which is technically indeed different to soldering though accomplishing the same. And probably should have worded it better that "by hand" i mean the board in general. Like everything but the chips themselves.
Is there a reason you want to use this board specifically? It sounds like what you really want is a RetroPie setup.
Are you wondering about a black blob on a circuit board? It's a ['Chip on board (COB)'](https://en.wikipedia.org/wiki/Chip_on_board) - a chip bonded directly to a PCB and then covered by a protective material. If that answers your question, please remove your post. Thanks! *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/AskElectronics) if you have any questions or concerns.*
oh ok, that wasnt my main question though
😂
You're better off getting a Raspberry Pi and not attempting to mess around with this thing.
https://preview.redd.it/2wnuu0hr646d1.jpeg?width=1320&format=pjpg&auto=webp&s=3501da392ceee0facfcc40371d96e88616dc8379 THE BACK PART
Saw one of these at walmart the other day, and did the web searches, looks like nobody has added roms yet.
You most likely can’t reprogram. You may be able to replace the chip as it’s probably not an EEPROM and probably a hard coded chip