From: Baltissen, GJPAA (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2004-09-09 07:46:50
Hallo allemaal,
I posted the source of my 8250 diskcopy program. The question arrised why
this and other programs were so slow. I thought that the reason was that
every byte was sent with the complete circus of ATN, LISTEN etc. I checked
that yesterday and... it isn't. But what puzzles me: I send the bytes in
blocks of 256 bytes. And the last one is received with EOI = True. And that
is what I do not understand. The routine that sends the 256 bytes:
J_0361 ldx #$06
jsr P_FFC9 ; $FFC9
ldy #$00
sty $01
B_036A sty $00
tya
lda ($01),Y
sei
jsr P_FFD2 ; $FFD2
cli
; lda $90
; bne B_037C
ldy $00
iny
bne B_036A
B_037C jsr P_FFCC ; $037C , $FFCC
rts
What tells $FFD2 to send the last byte with an acive EOI ????
--
___
/ __|__
/ / |_/ Groetjes, Ruud
\ \__|_\
\___| URL: Ruud.C64.org
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