Search the Community
Showing results for tags 'chip'.
-
I know but to be honest, there really aren't many resources out there. So I thought I'd throw one here. https://www.facebook.com/SExmortus/posts/10206970892982775 Amiga 500 Rev5 Mainboard, 1MB chip mod. First I have to replace the old Fat Agnus chip (8370) with a newer Fatter Agnus (8372A). Replacing the 8370. (Video) https://www.facebook.com/SExmortus/videos/10206970899342934/ Next I have to cut the JP2 trace between the middle and left (lower) pads next to the CPU and ROM chips. This trace tells Agnus to be ready for 512k (the way it is connected now) or 1MB chip (the way it will be after I connect the middle and right (upper) pads. If my male pin headers were here I would have just installed pins and a jumper. To give you an idea of the scale we are dealing with here. That's the tip of a razor sharp Xacto knife blade I'm using to cut that trace. I can no longer see well enough to do these things without the macro zoom video and light of my Galaxy Note 2. Sorry video is upside down. Video: https://www.facebook.com/SExmortus/videos/10206971136908873/ And I'll skip over a few things. First, I tried using the "Conductive Ink" trick but that didn't pass continuity like it should have. The ink pen was at least 8 years old and I really had to abuse it to get some ink out so there's that. Anyway, I'm just cleaning it up now getting ready to spot solder the pads. https://www.facebook.com/SExmortus/videos/10206973206760618/ And of course I do something I do not like.. https://www.facebook.com/SExmortus/videos/10206973265002074/ Cleaning up my mess. https://www.facebook.com/SExmortus/videos/10206973407605639/ Now it's time to cut another trace.. https://www.facebook.com/SExmortus/videos/10206976442641513/ Done and clean... Time to check my work... And done.
-
Afternoon all... so i recently found and decided to hook up my old supradrive to my atari st to look at some old files on there (i`m a working musician and used the ST extensively during the 80`s / 90`s... upon power up i heard a bit of a "crack" from within the casing !!!! ... so i opened her up and a couple of chips on what looks like the controller board were fried ... a quick look on the web meant that i could source the affected chips still and relatively cheaply (hurrah!) ...BUT..... one of the affected chips seems to be a custom programmed EPROM.. and i was wondering if anyone has or knows where to get the file i need to re-burn the new chip as my drive is useless without it .... alternatively can anyone suggest an alternate housing i could source so i can swap the actual HD over ... see piccy`s for the lowdown ... affected chips are 74HCT240N X 1 Easily available S7407N X 1 " " PAL16L8ANC X 1 " " CUSTOM EPROM.. Thanks for any advice / help offered.. steve
-
I've been meaning to start a topic about my abbuc hardware competition entry, a replacement for the Pokey chip. It's been mentioned in a couple of threads but I thought many people may have overlooked it. I tried to be sensitive to cost in my design, though once the full details are released (after competition result) it will be fun here to brainstorm ideas to make it even cheaper! Clearly there are still plenty of real pokey chips, however the supply is starting to become more limited and prices are on the increase. --- PokeyMAX Introduction The PokeyMAX is a complete replacement for the Pokey chip. It is derived from the work on the EclaireXL project, a complete FPGA based Atari 800XL clone. The intention is to build replacements for all of the Atari custom chips using this technology and Pokey has been built first. It can be used either to replace a broken/missing pokey, as a stereo upgrade, or just for fun! Features If pokey is socketed, zero wire installation (mono) Dual pokey mode Pins for 3 audio outputs (left channel/right channel/mixed) Small footprint, only a few mm larger than original IC Supports all features: 8x paddle inputs, IRQ, serial I/O, audio output, two tone mode, high pass filter and keyboard scan High level of compatibility Digital logic The PokeyMAX is built around the Altera MAX10 FPGA. This was chosen due to its integrated flash memory, power conversion, small size and low cost. The contained logic itself is described in VHDL and Verilog and then synthesized using the Quartus II software. Level conversion Most modern FPGAs no longer support 5V logic. While it is possible to find a few they are a vanishing breed. The MAX10 only supports up to 3.3V logic, so an IDT quickswitch level converter IC is used to connect to the high speed lines (A/D/IRQ/serial io etc) safely. Chip select Unfortunately I needed more level conversion lines than provided. TI came to the rescue with some 5V tolerant multi-function logic chips with which I was able to combined CS/!CS into one. Power The MAX10 requires a single 3.3V power supply, it then internally generates the rest of its supplies. This is very convenient, since often FPGAs require 3 or more different voltage levels. There is a switch mode regulator (LM3670) to convert from 5V to 3.3v in an efficient fashion. Paddles These are handled by charging a capacitor that we then check the level of using an LMV339. This is similar to the well-known LM339 comparator, except much smaller! The comparator is used since the level can be set very precisely rather than relying on when the FPGA detects a logic high. The level itself is set to 2.2v using the voltage divider on the right. It is also convenient since its open drain output means there are no level conversion issues. For the drain transistors, a 5V tolerant IO extender chip is used. The FPGA communicates with this over an I2C bus. Keyboard scan An IO extender chip drives the 6 keyboard lines and then reads the response. This is convenient since it only requires an I2C bus to the FPGA and the IC is much smaller than the level converters. JTAG The core may be upgraded or debugged using an Altera USB blaster connected here. Several of the JTAG pins are dual use and can be used as general IO. So we could for instance in future plug in i2c devices here or use for A5 (with external level converter) to allow quad pokey or sid etc. Audio filter The audio output uses a delta sigma dac. An RC circuit is used as a simple audio filter to smooth the output from this. There are four audio outputs, which are currently fed to pin 37 and 3 header pins (left/right and mixed). Note that the next stage much not draw a lot of current from the rc filter or it will cause distortion. A4 Pokey has 4 address pins (A0-A3). To make space for a 2nd pokey another address line is needed. For stereo connect to A4. Errata: Note that the "paddle capacitors" should not be populated and RA1 should be 0 ohm since these are already on the main board, this was a schematic error.
- 81 replies
-
- 38
-
One week ago I found that a forum member had cleaned up the die photos of the SP0256 (thanks JohnPCAE) and posted them on this thread. With all that work already done, it would only take a few days to get a simulation working! No, not from scratch, as over the course of the year I'd been working on a simulation of the AY-3-8500 PONG-clone chip based the visual6502 team's work. It was not too hard to use my earlier tools, code, and experience to turn the labeled die photos of the SP0256 into a javascript simulation. I managed to get a beta version working within a week! (That's RetroChallenge speed!) HERE is a copy I hosted on droppages. The source is on GitLab for anyone who knows JavaScript. This particular chip came from the Intellivoice expansion module, and contains 2 kilobytes of ROM for game related phrases (The ROM is the big rectangle on the middle right) If you zoom in on it, you can see the individual transistors (green) which encode "1"s in the ROM. The chip has a lot of transistors, 15681 to be exact (and that's not counting the pullup transistors.) These and the 4255 electrically isolated nodes are combined to form a list of 39432 polygons (glad I processed these automatically.) Its still a WIP, I fixed about two dozen errors in the highlighting and my code, but there are still some preventing the all of the circuitry from working properlly. For example, the instruction decoder is not disabled while a new instruction is being shifted in, resulting in spurious instructions activating. Once all bugs are ironed out, we'll have correct schematic files, potentially leading to better real time emulation. In the meantime, I'll keep posting updates on this forum and my blog
- 1 reply
-
- 5
-
- Intellivoice
- SP0256
-
(and 2 more)
Tagged with:
-
I wanted to add my question into the correct post/forum, so hopefully I've done that, if not, I apologize. I’m looking to learn more about this Atari 2600 that was given to me. Atari 2600 Property of Atari Inc. Sunnyvale, CA 94086 Manufactured: 1977 Manufactured by: TRW Electronic Components Company In Taiwan Model: CX-2600 Box: Copyright Atari, Inc. 1978 Light or Heavy Sixer: Not sure? I have a question (or maybe questions) about my Atari 2600 (CX-2600) that was given to me several weeks ago. A friend of mine passed away in 2007 (age 38) due to a chronic disease that he had all his life, and I've kept in contact with his Mom for the past 6 years. She learned (from my e-mail signature) that I liked Atari. She asked if I wanted her son's (Charley) Atari 2600, because it had been sitting in the closet for 25+ years. I said yes. She sent the Atari 2600 with the original box (Copyright Atari, Inc. 1978), but the motherboard inside reads copyright logo © 1977. She said they got it for Charley the first Christmas that the Atari came out, so why would the box read 1978? I opened the console and took it apart to clean the inside. I was shocked to see that it was spotless. The inside cover of the Atari console was a bit dusty, but other than that, it looks and works great. The switch board and main motherboard both read © 1977 (pictured), but 3 out of 4 chips (4th has no date on it) read 8108, 8120, and 8121, which I thought that meant the year (1981) and the 8th, 20th, and 21st weeks of that year. I noticed the piece of paper taped to the top of the EMI shield cover reads the letter Z (it could be 2), and also the date (in red) July 13th 1981. From what I've gathered from the enclosed photos (with detail), my friend received his Atari 2600 in 1978 (made in 1977), but... had it worked on in July of 1981. Something must have happened to where they had to replace 3 out of the 4 chips inside the console. They didn't have to replace anything (chips) on the switch board, just the main motherboard. I could be incorrect about my assumption(s). None of the boards have been replaced. Does this all mean they had it repaired in 1981? Why does the box read 1978 when it was built in 1977, unless it was built in late 1977? Is this Atari 2600 a Heavy Sixer? It looks more like a light sixer. I noted which chips were replaced. I apologize for the flashlight, but I wanted to note the dates perfectly. Again, I apologize for so many pictures, but I've read on here that people want pictures if someone is having a problem or question. Thank you for your help.
- 11 replies
-
- Motherboard
- Chip
-
(and 3 more)
Tagged with:
-
hey guys , i have a mssiah synthcart from 8-bit ventures for my c-64 and i was wondering if there exists anywhere a synthcart for the atari 8-bit machines to access the pokey chip in a similar way as mssiah. i have looked every where and even asked 8-bit ventures if they would do one and they said they had no intentions of making one . if one does'nt exist, is there anyone that knows basic well enough to make something like this ? could put the program on a flashcart maybe ? and modify the computer with midi? Also does anyone do midi modifications to the 800xl ? i just really want to be able to control the pokey chip through my daw and midi sequence it like i do with my c64. i love the way the pokey sounds , probably even over the SID. any good direction on this would be awesome . please help i have been trying for well over a year for a solution . thanks alot
-
Not exactly a home run of FLAVOUR (with a U) and texture.
-
I need help for a colecovision repair. When I plug any controllers on port 2 of my colecovision, the triggers won't work, even if they work in port 1. I've ordered some controller chip and soldered a new one but the triggers still doesn't work. I don't know what to do anymore but I don't want to throw it away and buy another colecovision, this one is important for me. If someone could help me I would really appreciate it. Thank you for your time^^
- 7 replies
-
- colecovision
- coleco
-
(and 4 more)
Tagged with:
-
Hey there, im looking for a programmer familiar with intellivision basic . to write a very simple program that is basically like a modded ,more in depth version of the intellivision synth stock program that comes on the ECS . i use and love whats there by default but i would love to cycle through some more sounds to play . and if it could be made to load through the tape data slot on the ECS that would be awesome as well ,as there is not a valid multicart out anymore . id be willing to pay a bit and it would also be helping the community as well . thanks . !!