Fix the UART, and set it to 19k2 for more stable operation. Make the downloader a...

[fpgaboy.git] / xm.asm

diff --git a/xm.asm b/xm.asm
index d4b53746a2a8aff3318e45e8ecefe7f218981625..3a4b25e90f3f33a69ed2cac96ac46830e01d1216 100644 (file)
--- a/xm.asm
+++ b/xm.asm
@@ -1,24 +1,23 @@
        SECTION "wee",HOME[$0]
        ; this all needs to be PIC!
-st:
-       ld sp, $CFFF
-       xor a
-       ld hl, $FF60
-       ld [hli], a
-       ld [hli], a
-       ld [hli], a
+;      xor a
+;      ld hl, $FF60
+;      ld [hli], a
+;      ld [hli], a
+;      ld [hli], a
+st:    ld sp, $CFFF
 nak:
        ld a, $15       ; NAK
        call putc+$FF80
        
 .ack:  call getc+$FF80
-       cp $01  ;SOH
-       jr z,.soh
+;      cp $01  ;SOH
+;      jr z,.soh
        cp $04  ;EOT
        jr z, .eot
        cp $18  ;CAN
        jr z, .rst
-       jr .donak
+       jr nak
 
 .eot:
        ld A, $06       ; Ack the EOT
@@ -27,26 +26,24 @@ nak:
 
 .soh:  call getc+$FF80 ; blk
        call getc+$FF80 ; iblk
-       xor a
-       ld b, a
-       ld l, a
-       ld h, $C0
-.lp:   call getc+$FF80
+       ld b, $00
+       ld hl, $C000
+.lp:   bit 7, l
+       jr nz, .cksm
+       call getc+$FF80
        ld [hli], a
        add b
        ld b, a
-       bit 7, l
-       jr z, .lp
+       jr .lp
 .cksm: call getc+$FF80
        cp b
        jr nz, .donak
        ld hl, $C000
-.lp2:  jr z, .doack
-       ld a, [hli]
+.lp2:  ld a, [hli]
        ld [$FF63], A
        bit 7, l
        jr z,.lp2
-.doack:        ld A, $06
+.doack:        ld A, $06       ; 06
        call putc+$FF80
        jr .ack
 .donak:        call getc+$FF80         ; Wait until the line clears, and then once
@@ -54,7 +51,7 @@ nak:
 
 getc:
        xor d
-       xor e
+       ;xor e  ; Possibly not needed?
 .dgetc:
        dec de
        xor a
@@ -66,11 +63,12 @@ getc:
        ld a, [$FF52]
        ret
 .timeout:
-       ld hl, $D000
+       ld hl, $D010
        ld a, [hl]
        inc a
        ld [hl], a
        ld [$FF51], a
+       pop hl
        jr nak
 
 putc:
@@ -84,5 +82,5 @@ putc:
        ld [$FF52],a
        ret
 
-       section "a", HOME[$7F]
-       nop
\ No newline at end of file
+       section "a", HOME[$7E]
+       nop