spi.s

来自「AVR系列单片机ATMEGA64开发的LED显示屏程序 内容包括ATMEGA6」· S 代码 · 共 122 行

	.module spi.c
	.area text(rom, con, rel)
	.dbfile F:\dujiang\费显动态LED屏\下位机程序\spi.c
	.dbfunc e SpiWriteByte _SpiWriteByte fV
;           byte -> R16
	.even
_SpiWriteByte::
	.dbline -1
	.dbline 15
; #include <iom64v.h>	// change to the appropriate header file
; #include "spi.h"
; 
; 
; 
; /* spi_init function should be generated using the AppBuilder
;  */
; 
; /*
; **  SpiWriteByte() writes a byte to the SPI and waits until
; **  it has been transmitted. This function doesn't
; **  return any value back.
; */
; void SpiWriteByte(unsigned char byte)
; {
	.dbline 16
;     SPDR = byte;
	out 0xf,R16
L2:
	.dbline 17
L3:
	.dbline 17
;     while (!(SPSR & 0x80));
	sbis 0xe,7
	rjmp L2
	.dbline 18
;     byte = SPDR;
	in R16,0xf
	.dbline -2
L1:
	.dbline 0 ; func end
	ret
	.dbsym r byte 16 c
	.dbend
	.dbfunc e SpiReadByte _SpiReadByte fc
	.even
_SpiReadByte::
	.dbline -1
	.dbline 28
; }
; 
; /*
; **  SpiReadByte() first writes a byte (a dummy, since
; **  that byte is to generate clock signals to "poll" home
; **  the byte from the slave. The function returns the
; **  received byte.
; */
; unsigned char SpiReadByte(void)
; {
	.dbline 29
;     SPDR = 0x00;
	clr R2
	out 0xf,R2
L6:
	.dbline 30
L7:
	.dbline 30
;     while (!(SPSR & 0x80));
	sbis 0xe,7
	rjmp L6
	.dbline 31
;     return SPDR;
	in R16,0xf
	.dbline -2
L5:
	.dbline 0 ; func end
	ret
	.dbend
	.dbfunc e SpiReadDataReg _SpiReadDataReg fc
	.even
_SpiReadDataReg::
	.dbline -1
	.dbline 40
; }
; 
; /*
; **  SpiReadDataReg() reads the last byte in the SPI register
; **  without any clock signals generated. Could be used
; **  as reading the last byte received.
; */
; unsigned char SpiReadDataReg(void)
; {
	.dbline 41
;     return SPDR;
	in R16,0xf
	.dbline -2
L9:
	.dbline 0 ; func end
	ret
	.dbend
	.dbfunc e main _main fV
	.even
_main::
	.dbline -1
	.dbline 44
; }
; void main(void)
; {
	.dbline 45
; SpiReadDataReg();
	xcall _SpiReadDataReg
L11:
	.dbline 46
L12:
	.dbline 46
	xjmp L11
X0:
	.dbline -2
L10:
	.dbline 0 ; func end
	ret
	.dbend