drv_sam_spi.s

基于S3C2440处理器的sd卡驱动程序

;/*------------------------------------------------------------------------------
;[BASIC]
;{
;	[FILENAME]  drv_sam_spi.s 
;	[CONTENT]   this file complete to SPI Timing for Samsung
;	[AUTHOR]    xucao
;	[VERSION]   01.0.00.051124
;	[COMPANY]   APLUS COMMUNICATION TECHNOLOGY (BeiJing) CO.,LTD
;}
;
;[MOD]
;{
;	01.0.00.051220:
;		1.Create initial version
;}
;------------------------------------------------------------------------------*/

; Pin map of SPI
; CS   <--> GPC7
; CLK  <--> GPC5
; SDI  <--> GPC6

LCDCTL_IOSCR0_ADDR EQU 0x14000300		
LCDCTL_IOSCR1_ADDR EQU  0x14000302		
LCDCTL_IOSCR2_ADDR EQU  0x14000304		
LCDCTL_IOSCR3_ADDR EQU  0x14000306
LCDCTL_IOPDCR0_ADDR EQU  0x14000308
LCDCTL_IOPDCR1_ADDR EQU  0x1400030A		
LCDCTL_IOSCR4_ADDR EQU  0x1400030C		
LCDCTL_IOSCR5_ADDR EQU  0x1400030E

 	AREA    SAMSPI, CODE, READONLY
	ENTRY

	EXPORT spi_send_data
	IMPORT GPIOSTATE
spi_send_data
	STMFD SP!,{r2-r7,r14}				;save the register of this code using
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	ldr r6,=LCDCTL_IOSCR4_ADDR 			;r6 is the state register address of the gpio
	ldr r7,=GPIOSTATE
	
    mov r4,#0x08 						;send the data bit count
	ldrh r5,[r7] ;[r6]						;r5 is the gpio state data
	bic  r5,r5,#0x08						;set cs to low
	strh r5,[r6]
	nop
Loop
	and r2,r0,#0x80						;first send the r0
	cmp r2,#0
	bne sendhigh
	bic r5,r5,#0x6						;set clock,data to low
	nop
	strh r5,[r6]
	b BitCom
sendhigh
	bic r5,r5,#0x04						;set clock to low
	orr r5,r5,#0x02						;set data to high
	strh r5,[r6]
	nop
BitCom
	nop
	nop
	nop
	mov r0,r0,LSL #1
	sub r4,r4,#1	
	orr r5,r5,#0x04						;set the clock to high	
	cmp r4,#0
	strh r5,[r6]
	bne Loop
;start to send the 16 bits data
	mov r4,#16 							;send the data bit count
Loop1
	;ldr r5,[r6]
	and r2,r1,#0x8000					;first send the r0
	cmp r2,#0
	bne sendhigh1
	bic r5,r5,#0x6						;set the clock,data to low
	nop
	strh r5,[r6]
	b BitCom1
sendhigh1
	bic r5,r5,#0x04						;set clock to low
	orr r5,r5,#0x02						;set data to high
	strh r5,[r6]
	nop
BitCom1
	nop	
	nop
	nop
	mov r1,r1,LSL #1
	sub r4,r4,#1
	orr r5,r5,#0x04						;set the clock to high	
	cmp r4,#0
	strh r5,[r6]	
	bne Loop1
	
    	orr  r5,r5,#0x08						;set cs to high
	strh r5,[r6]

	LDMFD SP!,{r2-r7,pc}				;save the register of this code using
	END