CodeWalrus

Development => Hardware => Topic started by: c4ooo on December 22, 2017, 11:18:00 pm

Title: z80 computer with arduino coprocessor.
Post by: c4ooo on December 22, 2017, 11:18:00 pm
I built a prototype for a z80 computer that uses an arduino for communication and bootstrapping. I can assemble a z80 source program with brass, and send it to the arduino with a small python program. The arduino is running a firmware program that waits for a program to be sent over serial, which it loads into the ram chip for the z80 to execute. The z80 communicates with the arduino via IO requests. The arduino<-->z80 API only contains 3 commands, but these can be used for the z80 to send messages to the PC via serial.

This is a small test program to send "test1" and "12345" to the PC via serial:

#define output(x, y) ld a,y \ out (x),a
#define command(x) output(PORT_COMMAND, x)
output(PORT_ADD_LOW, writeTo & FFh)
output(PORT_ADD_HIGH, writeTo >> 8) ;set data act-on address to writeTo
ld hl,string1
ld de,writeTo
ld bc,6
ldir ;copy string1 to writeTo
command(COMMAND_WRITE_SERIEL) ;tell arduino to send data from act-on address to PC
;stuff
ld hl,string2
ld de,writeTo
ld bc,6
ldir ;copy string2 to writeTo
command(COMMAND_WRITE_SERIEL) ;tell arduino to send data from act-on address to PC
jr $ ;do nothing
string1:
.db "test1",0
string2:
.db "12345",0
writeTo:


Picture:
(https://i.imgur.com/Q77AmVo.jpg)

Todo:
Title: Re: z80 computer with arduino coprocessor.
Post by: Juju on December 23, 2017, 12:53:20 am
Ooooh, sounds fun. Any idea what you want to do with this?
Title: Re: z80 computer with arduino coprocessor.
Post by: c4ooo on December 23, 2017, 02:20:09 am
Quote from: Juju on December 23, 2017, 12:53:20 am
Ooooh, sounds fun. Any idea what you want to do with this?

I dont know, i wanted to build something in the spirit of the Ninjabyte ZPX-128 ( https://codewalr.us/index.php?topic=1001.0 ) And had the part laying around. My main changes from the ninjabyte will be the use of an arduino 'stead of a Parallel Propeller (This can be an arduino mega shield), and the use of an LCD not VGA output.