It's not my blog post, but I can answer questions about the chip.
I had the Coleco Telstar arcade and all its cartridges, thanks to my parents. I was just a young kid at the time. Thank you for this deep dive into a chip that shaped my childhood.
Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
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Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#22This seems like a lot of transistors for such a simple game....
If they could reduce the number of scanlines on the monitor, they could get many hundreds of clock cycles per pixel, and then do everything in software. 512 instructions seems quite possible for that - compare to 'boot sector games' which run in about one third of the space.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#23It's not my blog post, but I can answer questions about the chip.
If I were you, I would try to reach to the blog poster.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#24The MOS 7601 was the first CPU I learned how to write code for, circa late 1977 to early 1978. I would scour jumble sales for broken pong games and the other, more sophisticated console variants to cannibalize for parts, with one conversation about haggling with another buyer over who got what parts leading to a job. There were several machines of the time that had pluggable cartridges, from Binatone, Telarude?/Telal…
This comment discusses how ball and paddle collision detection worked but leaves open the question of how the ball position was known. https://news.ycombinator.com/item?id=32862403
Given your experience programming for it can you provide any insight to how this may have been done?
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#25This seems like a lot of transistors for such a simple game.... If they could reduce the number of scanlines on the monitor, they could get many hundreds of clock cycles per pixel, and then do everything in software. 512 instructions seems quite possible for that - compare to 'boot sector games' which run in about one third of the space.
There are a couple of problems with that approach. First, the game uses a standard television, so you can't change the number of scanlines. Second, the pixel rate is about 1MHz, so you'd get about one clock cycle per pixel with a processor of that era. Of course, doing everything in software was a long-term solution.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#26Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#27The MOS 7601 was the first CPU I learned how to write code for, circa late 1977 to early 1978. I would scour jumble sales for broken pong games and the other, more sophisticated console variants to cannibalize for parts, with one conversation about haggling with another buyer over who got what parts leading to a job. There were several machines of the time that had pluggable cartridges, from Binatone, Telarude?/Telal…
Are you sure you're talking about the same chip? None of this is consistent with what I see on the die.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#28The MOS 7601 was the first CPU I learned how to write code for, circa late 1977 to early 1978. I would scour jumble sales for broken pong games and the other, more sophisticated console variants to cannibalize for parts, with one conversation about haggling with another buyer over who got what parts leading to a job. There were several machines of the time that had pluggable cartridges, from Binatone, Telarude?/Telal…
This comment discusses how ball and paddle collision detection worked but leaves open the question of how the ball position was known. https://news.ycombinator.com/item?id=32862403 Given your experience programming for it can you provide any insight to how this may have been done?
Yeah! when he mentioned making a timer by charging a cap and letting it discharge... that could apply to the ball position registers... it could also explain how they did various angles when there's no obvious multi-bit ALU.... varying dis/charge ratio...
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#29The MOS 7601 was the first CPU I learned how to write code for, circa late 1977 to early 1978. I would scour jumble sales for broken pong games and the other, more sophisticated console variants to cannibalize for parts, with one conversation about haggling with another buyer over who got what parts leading to a job. There were several machines of the time that had pluggable cartridges, from Binatone, Telarude?/Telal…
There were datasheets with the instruction set? But why does the article say that they were, until very recently, not sure whether it's a microcontroller?
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#30Earlier quoted context omitted.
It's a nice hack. I think this is how Woz did the Apple II paddles, too (albeit with discrete components and a timer IC). It sounds familiar.
Yes, the Apple II also uses a resistor-capacitor timing circuit to determine the paddle position. The big difference, however, is that the Apple II uses the timer and a counter to produce a paddle position 0-255. Software can then use this value to e.g. draw a paddle at a position on the screen. The game chip, on the other hand, doesn't produce a value. Instead, the timer is synchronized to the screen drawing, so whe…
capacitor charge/discharge timing is actually pretty common way to make ADC, even precision ones,