so trying to get my things up and running, I wrote a program for the PRU in asm to toggle 2 pins and read 4.
In C, I manage to manipulate them because I’m using GPIO.
But in asm… I try to interact with r30 and r31, and nothing really happens…
I"m with kernel 3.15.
Could someone guide me ?
I think I have to add a dts to declare pins and pinmux, but I feel a bit lost on this point.
In case, this is my asm source
/* enable ocp wide accesses */
LBCO r0, CONST_PRUCFG, 4, 4
CLR r0, r0, 4
SBCO r0, CONST_PRUCFG, 4, 4
/* prepared pru to host shared memory */
MOV r0, 0x000000120
MOV r1, CTPPR_0
ST32 r0, r1
MOV r0, 0x00100000
MOV r1, CTPPR_1
ST32 r0, r1
MOV r10, 0
MOV r11, 0
MOV r12, 0
/* main /
SET r30.t15 / CLK high /
MOV r10, r31.b0 / Read in the data */
QBBC CHKSENSOR2, r10.b0.t0 /* if r10.0, set r11.0 /
SET r11, 0
QBBC CHKSENSOR3, r10.b0.t1 / if r10.1, set r11.15 /
SET r11, 15
QBBC CHKSENSOR4, r10.b0.t2 / if r10.2, set r12.0 /
SET r12, 0
QBBC ENDCHECK, r10.b0.t3 / if r10.3, set r12.15 */
SET r12, 15
CLR r30.t15 /* CLK low /
LSL r11, r11, 1
LSL r12, r12, 1
ADD r0, r0, 1
/ store results from r10,r11 into host memory */
SBCO r10, CONST_PRUSHAREDRAM, 0, 8
/* signal cpu we are done (never reached) */
MOV r31.b0, PRU0_ARM_INTERRUPT + 16