Symbiosys a 6502 operating system for IDE hard disks units. [email protected]
This is a disk opperating system I wrote on a 1978 SYM-1 microcomputer a few years ago. I do intend getting back to this and recoding it in a real assembler rather the the Sym's Resident Assembler Editor (which actually is a very good resident assembler environment once it's patched to use Symbiosys filesystem.
I've started uploading the documentation in the Wiki, all will be explained in time.
Get back to me if there is actually anyone interested in it, once recoded in any normal assembler it could easily be ported to any computer, it uses the VIA ports to transfer the data to and from the IDE disk so no interface hardware other than wires from the VIA to the IDE.
Here is how my colleague mapped the interface out...
Connecting a 6522 VIA to an ATA IDE bus
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Designed for a Synertek SYM-1, and its AA Expansion connector.
PORTB0-7 maps to DATA0-7 on IDE
PORTA0 = ADDR0
PORTA1 = ADDR1
PORTA2 = ADDR2
PORTA3 = /RD
PORTA4 = /WR
PORTA5 = /CS0
AA-pin AAname* IDE
1 GND 2,19,22,24,26,30,40,Power-
3 A1 15 (DATA1)
7 B5 37 (/CS0)
8 B3 25 (/RD)
9 B1 33 (ADDR1)
10 A7 3 (DATA7)
11 A5 7 (DATA5)
12 A3 11 (DATA3)
13 RESET 1 (jumpered)
A Vcc Power+
C A2 13 (DATA2)
D A0 17 (DATA0)
J B4 23 (/WR)
K B2 36 (ADDR2)
L B0 35 (ADDR0)
M A6 5 (DATA6)
N A4 9 (DATA4)
27 (IORDY) - tie low 10kR
29 (DMACK) - tie high 1kR
38 (/CS1) - tie high 1kR
39 (DASP) - LED+180R to Vcc
*: as I discovered when debugging the code, what the SYM1 calls PORT A on its AA expansion bus, is actually PORTB to the 6522. The pinout is no different, since I ended up changing the code to suit.
-- Chris Baird,, [email protected] Feb2010. Corrected IORDY and DASP: 2010-Jul-31