Still struggling with a 6551 (rockwell)

From: didier_at_aida.org Date: Fri, 27 Oct 2023 14:45:38 +0200 Message-ID: <d0e35a61-c5dd-4173-a5c8-fc4f442a3f8f_at_aida.org>

I'm still struggling with the Rockwell 6551

I probably did something wrong but I can's see what

RX / TX are connected

CTS/RTS are not connected

DSR/DCD/DTS are not connected

my code:

ACIA_RXD        =       $00
ACIA_TXD        =       $00
ACIA_SR         =       $01
ACIA_CMD        =       $02
ACIA_CTL        =       $04

ACIA    =       $D000

CONINIT:       .PROC
                         LDA     #$00            ;- reset ACIA
                         STA     ACIA+ACIA_SR
                         LDA     #$1E            ;- 9600 bauds [internal 
baud], 8 bits, 1 stop
                         STA     ACIA+ACIA_CTL
                         LDA     #$CA            ;- no parity, no interrupt
                         STA     ACIA+ACIA_CMD
                         LDA     ACIA+ACIA_RXD   ;- clear receive buffer
                         JMP     CLEARTABS
                         .PEND

CONIN:          .PROC
                         PHP
_LOOP            LDA     ACIA+ACIA_SR
                         AND     #%00001000
                         BEQ     _LOOP
                         LDA     ACIA+ACIA_RXD
                         PLP
                         RTS
                         .PEND

CONOUT:      .PROC
                         PHP
                         CMP     #ASCII_HT       ;- is tab ?
                         BNE     _SKIP
                         JSR     PROCESSTABS
                         PLP
                         RTS

_SKIP              JSR     ROWCOL  ; adjust row/col
                         PHA

_LOOP            LDA     ACIA+ACIA_SR
                         AND     #%00010000
                         BEQ     _LOOP
                         PLA
                         STA     ACIA+ACIA_TXD
                         PLP
                         RTS
                         .PEND

this code is part of my 6502 debugger...

I guess I did something wrong,

any idea ?

thanks