🚀 go-pugleaf

>>>>> On 1 Oct 1992 07:39:13 GMT, mats.astrom@neurofys.uu.se (Mats Astrom) said:
Mats> NNTP-Posting-Host: mats.neurofys.uu.se

Mats> While doing DMA-transfer it's possible to read the number of transfers done
Mats> by reading a specific register of the DMA-circuit. I've manage to do so but
Mats> the result seem to be somewhat instable ! The instability is due to reads of
Mats> the register in the middle of a transfer, isn't it ????
Mats> Assuming I'm setting up everthing correctly, how do I read the number of
Mats> transferred bytes to get the correct value every time ?????

Few questions:
1. did you remember to reset hi/lo flip-flop (I/O address 0Ch)
   before reading the DMA count register ?
2. do you remember the DMA count register contains remaining count,
   not count transferred and it goes down to -1 ?
3. why read registers many times (the repeat)? read once:
   port[DmaRstFF]:=0;
   l1:=port[DmaCntReg]; h1:=port[DmaCntReg];
   l2:=port[DmaCntReg]; h2:=port[DmaCntReg];
   IF h1<>h2 THEN cnt:=(h1 SHL 8)+l1 ELSE cnt:=(h2 SHL 8)+l2;
   Let me know if it gives stable results (i.e. still going down).
Jerzy Tarasiuk