Baking Pi, OK 03, B+ - Raspberry Pi Forums

i have 2 questions:

firstly, in setgpiofunction function says add 4 gpio address, stored in r0, each loop, write directly address in r0.

code: select all

	functionloop:  		cmp r2,#9 		subhi r2,#10 		addhi r0,#4 		bhi functionloop 	//stuff 	str r1,[r0]

worked setting r3 0, adding 4 r3 each loop, writing address in r0 offset of r3:

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	functionloop:      // address didn't work. 		cmp r2,#9 		subhi r2,#10 		addhi r3,#4 		bhi functionloop 	// stuff 	str r1,[r0,r3]

why didn't first work? not same thing?

secondly, tutorial said include

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pinbank .req r3 lsr pinbank,pinnum,#5 lsl pinbank,#2 add gpioaddr,pinbank .unreq pinbank

code didn't work until removed section.

interestingly tryed follow tutorial pi 1 b+ , can select pins of pins dont work....

atleast compile program, can try code register 3 fix?

gpio api:

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/* function normal gpio address */ .globl getgpioaddress  				/* accessable everyone*/ getgpioaddress:						/* label */ ldr r0,=0x20200000					/* load gpio address r0 */ mov pc,lr							/* return main programm */ /*---------------------------------------------------------------------------------*/ /* function sets gpio pin function */ /* r0 contains gpio address, r1 contains function code, r2 contains pin number */ .globl setgpiofunction				/* accessable */ setgpiofunction:					/* label */ cmp r0,#53 							/* failsafe (if desired pin >=53 yes 53 because of internal pins!) */ cmpls r1,#7							/* failsafe (if desired mode >=7) */ movhi pc,lr							/* return main programm( if in last compare a>b(register 0)>53 etc..)*/ push {lr}							/* save lr(link register) stack */ mov r2,r0							/* save gpio bus address r2 */ bl getgpioaddress					/* gpioaddress r0 (function coded r0) bl updates link register call method*/ functionloop$:						/* label helper function because devision slow*/ cmp r2,#9							/* compare pinnumber 9 pin number 0-9 */ subhi r2,#10						/* if compare a>b pinnumber -10 */ addhi r0,#4							/* if compare a>b gpio address +4 */ bhi functionloop$					/* if compare a>b go loop start */ add r2, r2,lsl #1					/* faster multiplication 3 */ lsl r1,r2							/* shift because want set pin number */ str r1,[r0]							/* store r1 register 0  */	 pop {pc}							/* return mov pc,lr */ /*---------------------------------------------------------------------------------*/ .globl setgpio setgpio: pinnum .req r0 pinval .req r1 cmp pinnum,#53 movhi pc,lr push {lr} mov r2,pinnum .unreq pinnum pinnum .req r2 bl getgpioaddress gpioaddr .req r0 pinbank .req r3 lsr pinbank,pinnum,#5 lsl pinbank,#2 add gpioaddr,pinbank .unreq pinbank , pinnum,#31 setbit .req r3 mov setbit,#1 lsl setbit,pinnum .unreq pinnum teq pinval,#0 .unreq pinval streq setbit,[gpioaddr,#40] strne setbit,[gpioaddr,#28] .unreq setbit .unreq gpioaddr pop {pc}

3led on ports 25,6,18 turn on , off ~1sec delay:

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.section .init .globl _start _start: /*-fehler: 26,21,20-----------------------------------*/  loop$:  /*---------------------------------------------------------------------------------*/ pinnum .req r0 pinfunc .req r1 mov pinnum,#25 mov pinfunc,#1 bl setgpiofunction .unreq pinnum .unreq pinfunc /*---------------------------------------------------------------------------------*/ pinnum .req r0 pinval .req r1 mov pinnum,#25 mov pinval,#1 bl setgpio .unreq pinnum .unreq pinval /*---------------------------------------------------------------------------------*/ mov r2,#0x3f0000 wait1$: sub r2,#1 cmp r2,#0 bne wait1$ /*---------------------------------------------------------------------------------*/ pinnum .req r0 pinfunc .req r1 mov pinnum,#6 mov pinfunc,#1 bl setgpiofunction .unreq pinnum .unreq pinfunc /*---------------------------------------------------------------------------------*/ pinnum .req r0 pinval .req r1 mov pinnum,#6 mov pinval,#1 bl setgpio .unreq pinnum .unreq pinval /*---------------------------------------------------------------------------------*/ mov r3,#0x3f0000 wait2$: sub r3,#1 cmp r3,#0 bne wait2$ /*---------------------------------------------------------------------------------*/ pinnum .req r0 pinfunc .req r1 mov pinnum,#18 mov pinfunc,#1 bl setgpiofunction .unreq pinnum .unreq pinfunc /*---------------------------------------------------------------------------------*/ pinnum .req r0 pinval .req r1 mov pinnum,#18 mov pinval,#1 bl setgpio .unreq pinnum .unreq pinval /*---------------------------------------------------------------------------------*/ mov r4,#0x3f0000 wait3$: sub r4,#1 cmp r4,#0 bne wait3$ pinnum .req r0 pinval .req r1 mov pinnum,#25 mov pinval,#0 bl setgpio .unreq pinnum .unreq pinval mov r4,#0x3f0000 wait4$: sub r4,#1 cmp r4,#0 bne wait4$ pinnum .req r0 pinval .req r1 mov pinnum,#6 mov pinval,#0 bl setgpio .unreq pinnum .unreq pinval mov r4,#0x3f0000 wait5$: sub r4,#1 cmp r4,#0 bne wait5$ pinnum .req r0 pinval .req r1 mov pinnum,#18 mov pinval,#0 bl setgpio .unreq pinnum .unreq pinval mov r4,#0x3f0000 wait6$: sub r4,#1 cmp r4,#0 bne wait6$ b loop$    

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