initial commit

oled.mac

@@ -0,0 +1,198 @@
+.Z80
+ASEG      ; absolute addressing
+ORG  100h ; skip CP/M
+
+CR   EQU  0Dh       ; carriage return
+LF   EQU  0Ah       ; new line
+BDOS EQU  0005h     ; BDOS entry point
+PSTR EQU  09h       ; print string
+CRED EQU  01h       ; read console
+
+OLED EQU  50h  ; base addr of OLED card
+ORST EQU  04h  ; reset command (H)
+OBUF EQU  02h  ; chip select (L), buffer (H)
+ODB  EQU  01h  ; display byte (H)
+OCMD EQU  00h  ; command (L)
+
+; 4 rows of display
+OROWA EQU  0B0h  ; select top row
+OROWB EQU  0B1h  ; select second row
+OROWC EQU  0B2h  ; select third row
+OROWD EQU  0B3h  ; select bottom row
+
+OCOL0 EQU  04h  ; left most column
+OSELC EQU  10h  ; select column command
+OCOLL EQU  80h  ; column count: 128 columns
+
+; 128 columns from 4 to 131
+; 1Xh, 0Yh - XY = 04h to 83h
+
+; MAIN
+CALL OINIT     ; init OLED
+CALL OCLS      ; clear screen
+CALL PROMPT    ; print prompt
+
+CALL OCSTART   ; go to start 
+CALL READLINE  ; read row A
+CALL READLINE  ; read row B
+CALL READLINE  ; read row C
+CALL READLINE  ; read row D
+
+RET            ; exit to CP/M
+
+
+READLINE:
+     LD   D,OCOLL   ; number of columns
+READLINE1:
+     PUSH DE
+     CALL READHEX   ; read hex input from console
+     CALL ODATA     ; write to OLED
+     POP  DE
+     DEC  D         ; count donw columns
+     JP   NZ,READLINE1  ; next column 
+     RET
+
+OINIT:
+     CALL ORESET    ; reset OLED
+     LD   HL,OINITSEQ ; commands to send
+OINITLOOP:
+     LD   A,(HL)    ; load command byte to A
+     CP   0FFh      ; check if we are done
+     RET  Z         ; marker reached
+     CALL OCOMMAND  ; send command from A
+     INC  HL        ; next command
+     JR   OINITLOOP ; send next command 
+
+ORESET:
+     LD   C,OLED    ; base I/O address
+     LD   B,ORST OR OBUF ; RST H, /CS H, DB L
+     OUT  (C),A     ; write any A, to (C) + B
+     REPT 4
+          NOP       ; delay
+     ENDM
+     LD   B,OBUF    ; clear RST
+     OUT  (C),A     ; send
+     REPT 20
+          NOP       ; long delay
+     ENDM
+     RET
+
+OCLS:
+     CALL OCSTART   ; set start
+     CALL OCLSROW   ; clear row A
+     CALL OCLSROW   ; clear row B
+     CALL OCLSROW   ; clear row C
+     CALL OCLSROW   ; clear row D
+     RET
+
+; set cursor to start 
+OCSTART:
+     LD   A,OSELC   ; select column
+     CALL OCOMMAND
+     LD   A,OCOL0   ; column 0 
+     CALL OCOMMAND
+     LD   A,OROWA   ; select first row
+     CALL OCOMMAND
+     RET
+
+OCLSROW:
+     ;XOR  A        ; display byte to write (0)
+     LD   A,0FFh    ; turn on all pixels
+     LD   D,OCOLL   ; count columns in D
+OCLSROW1:
+     CALL ODATA     ; write A to displey
+     DEC  D         ; next column
+     JR   NZ,OCLSROW1
+     RET
+
+; A = command to send to OLED
+OCOMMAND:
+     LD   C,OLED    ; base I/O
+     LD   B,OCMD    ; send command
+     OUT  (C),A     ; send
+     REPT 4
+          NOP
+     ENDM
+     LD   B,OCMD OR OBUF
+     OUT  (C),A     ; send
+     REPT 10
+          NOP
+     ENDM
+     RET
+
+; Write to OLED memory
+; A = graphic byte to dispaly memory
+ODATA:
+     LD   C,OLED    ; base I/O
+     LD   B,ODB     ; select Data Byte mode
+     OUT  (C),A     ; output byte
+     REPT 4
+          NOP
+     ENDM
+     LD   B,OBUF OR ODB
+     OUT  (C),A     ; output byte
+     NOP
+     NOP
+     RET
+
+; Read byte from console
+READ:
+     LD   C,CRED    ; read from console
+     CALL BDOS      ; call CP/M
+     RET            ; A=CHAR
+
+; Reads 4 bit value (0-F)
+READNIB:
+     CALL READ
+     LD   B,41h     ; compare with 'A' (10)
+     CP   B
+     JP   NC,RNB1   ; A>=B
+     SUB  30h       ; sub '0'
+     RET
+RNB1:
+     SUB  41h-10    ; sub 'A'-10 
+     AND  0Fh       ; clear to 4 bits so 'a-f' also work
+     RET
+
+; Reads two bytes (0-F) from console
+; A = byte read
+READHEX:
+     CALL READNIB   ; read MSD nibble
+     SLA  A         ; shift 4 bits
+     SLA  A
+     SLA  A
+     SLA  A
+     LD   B,A       ; B=A
+     PUSH BC        ; save B
+     CALL READNIB   ; read LSD nibble
+     POP  BC        ; restore B
+     OR   B         ; OR B to A
+     RET
+
+PROMPT:
+     LD   C,PSTR    ; load function number
+     LD   DE,PROMPTMSG    ; load string addr
+     CALL BDOS      ; call CP/M
+     RET
+
+PROMPTMSG: 
+     DB   'OLED:>', CR, LF,'$' ; string terminated with $
+
+; Initialization sequence
+; 081h,080h - set contrast (080h full)
+; 020h,000h - set horizontal window wrapping
+; 021h,004h,083h - window full width
+; 022h,000h,003h - window full height
+OINITSEQ:
+     DB   0AEh,0D5h,0A0h,0A8h
+     DB   01Fh,0D3h,000h,0ADh
+     DB   08Eh,0D8h,005h,0A1h
+     DB   0C8h,0DAh,012h,091h
+     DB   03Fh,03Fh,03Fh,03Fh
+     DB   081h,070h,0D9h,0D2h
+     DB   0DBh,034h,0A6h,0A4h
+     DB   0AFh,020h,000h,021h
+     DB   004h,083h,000h,003h
+     DB   0FFh ; end marker
+
+END