Hard question about interface with SID module

[HL-SDK]

Ok, so I am learning how to write code for the wiring and arduino boards, and I have a sid module laying around. I want to interface with it like TK's amazing PIC does, but first I have to know how the shift registers are written to.

What is the process that the CORE writes to the SID module? Also, what is this MU, and SO connection for?

I'd just go for a parallel interface but the sid won't stay on my breadboard, it pops out, and anyway, the module is nice and clean :-p

[Wilba]

The names of the pins on the port of the SID module are a bit confusing because it was originally used for a different module.

I'll explain briefly... refer to the SID module circuit schematic.

SID CS pin (port pin SO) is normally high, pulsed low to enable the SID and the SID will read the address and data bits.

Port pin MU is the serial data bit (connected to SER). As port pin MD (connected to SCLK) is pulsed high, the state of MU is shifted into the shift registers, you do this 16 times to get 16 bits into the two shift registers, but they're not output yet, that's what pulsing RC does (connected to RCLK). You can see how O8 of one shift register connects to the SER of the second shift register, that's how the bits are shifted into both shift registers, and also will tell you what order you need to send the bits.

So that's basically it, CS stays high, write bits in with pulsing SCLK, output them with a pulse of RCLK, then pulse CS low to get the SID to read the bits. Refer to the 74HC595 datasheet as well... but the names of the pins will be different.

[HL-SDK]

Your explanation was simple and elegant, thank you very much for the help!!

(damn sid needing 2 power supplies)

Good thing I have +12, +5, and -12 all on the same breadboard ;-D

[HL-SDK]

I also noticed that since the SID has 5 pins for register selection, and one shift register output is used for reset, so there is a gap of nonsense bits :-p

This is getting tough to do in whatever code I am using now. IT's also tough because for some reason, you guys like complicating stuff with serial ;D

Anyway, what I'm doing now is finding a way I can write hex out through USB serial, have it interpreted and sent over into the SID. Then I might write some processing program or MAX or whatever to tell the sid what to do.

However TK managed to pull off Midibox, I may never know.