Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
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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
#2It's not my blog post, but I can answer questions about the chip.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#3"The way the paddles in particular are drawn is especially ingenious; in fact, the firmware doesn't even need to position them. The paddle controls are simple potentiometers feeding into an R-C circuit (external to the chip, not shown here) that discharges at a rate based on the pot's resistance. This then feeds into an on-chip comparator in the region marked "paddles," delaying drawing the paddle a number of scanlines based on the pot's position until the comparator triggers, thus eliminating the need for a more complex solution like an A-D converter (cheap!) and automatically drawing the paddle at the proper location without any intervention from the firmware."
I love it!
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#4It's not my blog post, but I can answer questions about the chip.
Thanks again, Ken, for your help with this!
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#5"The way the paddles in particular are drawn is especially ingenious; in fact, the firmware doesn't even need to position them. The paddle controls are simple potentiometers feeding into an R-C circuit (external to the chip, not shown here) that discharges at a rate based on the pot's resistance. This then feeds into an on-chip comparator in the region marked "paddles," delaying drawing the paddle a number of scanlin…
If you want the least amount of lag possible, you now know which device to turn to. I'm thinking of the famous lag table of character entry for 80s 8-bit computers and modern PCs.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#6It's not my blog post, but I can answer questions about the chip.
How close is it to the chip in the VCS? Was it a step towards the 6507?
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#7"The way the paddles in particular are drawn is especially ingenious; in fact, the firmware doesn't even need to position them. The paddle controls are simple potentiometers feeding into an R-C circuit (external to the chip, not shown here) that discharges at a rate based on the pot's resistance. This then feeds into an on-chip comparator in the region marked "paddles," delaying drawing the paddle a number of scanlin…
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.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#8very cool to see the engineering of that time.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#9"The way the paddles in particular are drawn is especially ingenious; in fact, the firmware doesn't even need to position them. The paddle controls are simple potentiometers feeding into an R-C circuit (external to the chip, not shown here) that discharges at a rate based on the pot's resistance. This then feeds into an on-chip comparator in the region marked "paddles," delaying drawing the paddle a number of scanlin…
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 when the timer fires, it indicates to draw the paddle now. So the system never has the paddle position as a digital value and there's no register that holds the paddle position.
Re: Confirmed the MOS 7600/7601 Pong chip is a true microcontroller
#10It's not my blog post, but I can answer questions about the chip.
How close is it to the chip in the VCS? Was it a step towards the 6507?
The 6507 chip was essentially a repackaged 6502 microprocessor. The game chip is pretty weird, with a custom microcontroller and a bunch of specialized circuitry. So I don't think there is any connection between them.