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Diffstat (limited to 'examples/serial.gbasm')
| -rw-r--r-- | examples/serial.gbasm | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/examples/serial.gbasm b/examples/serial.gbasm new file mode 100644 index 0000000..d4b4937 --- /dev/null +++ b/examples/serial.gbasm @@ -0,0 +1,73 @@ +; This ROM is a simple example of how to use serial connections. +; It will wait to receive text via the serial connection, save the text in memory until it encounters a new line (without overflow check), then send back in ASCII "Astatin" and a new line followed by the text that was received. + +.PADTO 0x0058 + JP =Serial_Recv + +.PADTO 0x0100 +Entry: + JP =Start + +.PADTO 0x0104 +Nintendo_Logo: ; The Nintendo logo must be stored in bytes 0x104-133 + .DB $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83,$00,$0C,$00,$0D + .DB $00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6,$DD,$DD,$D9,$99 + .DB $BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC,$99,$9F,$BB,$B9,$33,$3E + +.PADTO 0x0134 +Checksum: ; The bytes 0x134-0x14d need to add up to 0xe7 (= 0xff - 0x19) + .DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 + .DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$e7 + +Start: + LD SP, $fffe + + LD A, $00 + LD ($40), A + + LD A, $08 + LD ($ff), A + + LD HL, $c000 + EI + + Lock: + HALT + EI + JR =Lock + +Serial_Recv: + LD A, ($01) + CP $0a + CALL Z, =Read_back + LD (HL+), A + RETI + +Read_back: + LD (HL), $00 + LD HL, =Astatin_ASCII + CALL =Print + LD HL, $c000 + CALL =Print + JP =Start + +Astatin_ASCII: +.DB $41, $73, $74, $61, $74, $69, $6e, $0a $00 + +Print: + .send_loop: + LD A, (HL+) + CP $00 + RET Z + + LD ($01), A + + LD A, $81 + + LD ($02), A + + .wait_transfer: + LD A, ($02) + BIT 7, A + JR NZ, =.wait_transfer + JR =.send_loop |