3 Q's in 1 feed:

[ac.tomo]

Hi, I have 3 questions I would like information on if poss. please.

 

1. Does anyone know the operation codes for a US-DOUBLER chipped 1050, much appreciated if poss. thankyou.

2. Can anyone tell me the timing specifics of a SECAM ATARI?

3. Lastly, I have a program here that runs an IRQ HARDWARE TIMER, it works on the REAL ATARI Hardware BUT NOT on ALTIRRA, any help much appreciated.

 

10 POKE 53768,0

20 FOR I=0 TO 12:READ B:POKE 1536+I,B:NEXT I

30 DATA 173,10,212,41,240,141,10,212,141,24,208,104,64

40 POKE 528,0:POKE 529,6

50 POKE 53760,30

60 POKE 16,193:POKE 53774,193

70 POKE 53769,1

 

Thanks in advance.

 

[phaeron]

I'm getting the same behavior on a 130XE as in Altirra for that BASIC program -- it just turns the screen dark red/yellow. This is the IRQ handler POKE'd into $0600:

 

    0600: AD 0A D4          LDA $D40A
    0603: 29 F0             AND #$F0
    0605: 8D 0A D4          STA WSYNC
    0608: 8D 18 D0          STA COLPF2
    060B: 68                PLA
    060C: 40                RTI

 

There is no read register at $D40A (54282), so ANTIC returns $FF, and this ends up writing $F0 into the playfield color register. Did you mean $D40B (VCOUNT), by chance?

 

[ac.tomo]

Thanks for noticing that Phaeron, no I actually meant it to be $D20A (173 10 210 - the RANDOM number loc.), an oversight. The program does kind of work if you make a couple of changes to:

 

10 POKE 53768,1

20 FOR I=0 TO 9:READ B:POKE 1536+I,B:NEXT I

30 DATA 173,10,210,41,240,141,24,208,104,64

40 POKE 528,0:POKE 529,6

50 POKE 53760,30

60 POKE 16,193:POKE 53774,193

70 POKE 53769,1

 

The original STA $WSYNC causes the routine to take longer than the time you allow it in line 50, and although this now works without it, it won't if you change the clock speed on line-10 to anything other than #1.

 

Anyone know the answers to the other 2 questions I'm asking?

Edited November 12, 2022 by ac.tomo

[E474]

#1 is covered in my post in: 

 

[ac.tomo]

Thankyou E474. I've had a look and its exactly what I'm after, but, what does the PERCOM mean?

[E474]

Percom (block) is a way of describing the disk format of the current disk in the drive (sector size, number of sectors, etc), but it's not reliable for the US Doubler. I think it's in the Atari 8-bit FAQ, and this thread goes into a bit more detail (with example assembler code).  There's probably more information available via the forum site search.

 

 

[ac.tomo]

thanks for that E474.