SID chips and ARM chips
Yesterday, I received a small parcel containing two SID chips (6581) rescued from doomed Commodore 64s. My plan is to wire one of them up to the Arduino, which I'm currently doing. I'll need a 1MHz Phase2 clock, which means dividing down a 16MHz oscillator module with a 74HC393. Wish the Arduino had a 16MHz clock output pin! Once I have a clock, and the data and address pins connected, it'll be time to run some simulated 6502 bus cycles and get the chip to make sound!
As an antidote to the extreme frustration I find myself stuck with, I made a small purchase. It's another small microcontroller PCB, about the same size as the Arduino, but this one features a Philips (now called NXP) chip, the LPC2103 -- it's an ARM microcontroller! It's one of the smaller ones, with just 8k of RAM and 32k of Flash ROM. It has a built-in serial port bootloader, so with the proper software on the host, it'll load up and run with just a MAX232 buffer. Of course, it's the same low-level machine architecture as the Acorn Archimedes, but in a chip package that's about 8mm square.
I've made a little progress with understanding the Compukit UK101's video circuits, and I think I know how to eliminate the rather variable monostable pulse generators. The sync combiner that takes in horizontal and vertical sync and outputs composite sync is definitely wrong; that can be replaced by a 74LS86 ex-or gate.
The Great Z80 Purge Of 2009 has well and truly stalled. Must get the next two machines out of the spare bedroom and out of the house altogether! Will probably dig out the Acorn Archimedes machine(s), too (to keep of course). The Arduino video gadget that I mentioned before has appeared on the Make blog today. I'm starting to get somewhere with the Apple PowerMac 5500/275, thanks to a bit of desktop-fixing by aminorjourney; I have an RTL8139 PCI ethernet card in the single PCI slot, and I have a MacOS 8 driver for it.
As an antidote to the extreme frustration I find myself stuck with, I made a small purchase. It's another small microcontroller PCB, about the same size as the Arduino, but this one features a Philips (now called NXP) chip, the LPC2103 -- it's an ARM microcontroller! It's one of the smaller ones, with just 8k of RAM and 32k of Flash ROM. It has a built-in serial port bootloader, so with the proper software on the host, it'll load up and run with just a MAX232 buffer. Of course, it's the same low-level machine architecture as the Acorn Archimedes, but in a chip package that's about 8mm square.
I've made a little progress with understanding the Compukit UK101's video circuits, and I think I know how to eliminate the rather variable monostable pulse generators. The sync combiner that takes in horizontal and vertical sync and outputs composite sync is definitely wrong; that can be replaced by a 74LS86 ex-or gate.
The Great Z80 Purge Of 2009 has well and truly stalled. Must get the next two machines out of the spare bedroom and out of the house altogether! Will probably dig out the Acorn Archimedes machine(s), too (to keep of course). The Arduino video gadget that I mentioned before has appeared on the Make blog today. I'm starting to get somewhere with the Apple PowerMac 5500/275, thanks to a bit of desktop-fixing by aminorjourney; I have an RTL8139 PCI ethernet card in the single PCI slot, and I have a MacOS 8 driver for it.