wegi
KIM-1 User
Posts: 35
|
Post by wegi on Sept 14, 2017 17:26:04 GMT
Simple if we expect 20MHZ we can check this in assembler by:
0. Disable sprites $d015 = 0 and wait one frame
sei Lda #$00 Sta $d015 Bit $d012 Bpl *-3 Bit $d012 Bmi *-3
1. Wait for $d012 = 0
;Lda #$00 ;Acc = 0 before ldx #252
cmp $d012 bne *-3
2. Start the any delay loop with 63*20 cycles (1260 cycles)
dex ;252* 5 cycles bne *-1
3. Check $d012
lda $d012 cli
4. If $d012 >18 ...
Cmp #19 bcs we_gotta 1MHZ
cmp #9 bcs we_gotta 2MHZ
cmp #3 bcc we_gotta_SCPU
|
|
wegi
KIM-1 User
Posts: 35
|
Post by wegi on Sept 14, 2017 17:07:05 GMT
|
|
wegi
KIM-1 User
Posts: 35
|
Post by wegi on Sept 14, 2017 16:56:38 GMT
I'm guessing the subject is about the serial burst mode between commodore and 1571 with used additional SQR line. Also the BURST people called a hardware mod using additional 8 free lines from unused port of VIA and connected this to USER PORT in commodore. Also here was done hardware handshaking. Years ago I had this mod. Seriously this never did not convince me bcos often had a some write errors. So I leave this.
|
|
wegi
KIM-1 User
Posts: 35
|
Post by wegi on Sept 14, 2017 16:37:45 GMT
csdb.dk/release/?id=81316That's my old tool for use additional space on the disk on the illegal track's 36/41-42 We can talk about programming drives. I tried still compatibile between 1571/70/1541C/1541 II (1570/71 in single mode (GCR) without MFM of course). Some times like here www.youtube.com/watch?v=Q76ZepI_44Y you can do realtime 3d vertex calculated in drive. Sadly here is 2KB of RAM only. About tape is really little to say. Only ABC turbo. Sometimes people done IRQ tape loaders, but allways tape was very very slow. Even in ABC turbo
|
|
wegi
KIM-1 User
Posts: 35
|
Post by wegi on Sept 14, 2017 15:01:44 GMT
|
|