CCS 6.1.1 and PRU v2.1.1 mixed language

Ty Dean

I am learning the Beaglebone Black PRU tools and I would like to know if there are any examples of using mixed language C and assembly out there.

Currently I have a main.c with the entry point in C language. I have an assembly module linked into my project with the .asm extension. At the top of main.c I have an extern to an assembly function and I can successfully call and pass data and return data from the assembly function.

Most of the examples I've found are in pasm. I am trying to learn from these examples and do it in CCS.

The big question I have is:

" Is there a way to replace the functionality of .setcallreg from pasm in the v2.1.1 compiler/assembler? "

I can do .macros but I would prefer to do calls with a return. The .macros don't seem to play nice if they are nested. I am working with the Blackhawk USB100v2 emulator.

Any pointers to more information would be much appreciated.

Thanks,

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

I will ask the PRU experts to comment. You can also check this thread: e2e.ti.com/.../491923

0 Ty Dean over 9 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

I almost figured it out. I'm still clobbering my SPI_TX

I just wanted to share what I learned.

It's the JAL to the || label || command.

Still need to protect the registers.

Here is my main.c code:

* main.c

#include <stdint.h>

volatile register uint32_t __R30;

volatile register uint32_t __R31;

#define PRU0_PRU1_INTERRUPT (17)

#define PRU1_PRU0_INTERRUPT (18)

#define PRU0_ARM_INTERRUPT (19+16)

#define PRU1_ARM_INTERRUPT (20+16)

//extern uint32_t trySPI(uint32_t send_value); // assy function in gistfile1.asm

extern void trySPI(uint32_t send_value); // assy function in gistfile1.asm

extern void initIO(void); // assy function in gistfile1.asm

volatile uint32_t send_value;

int main(void) {

initIO(); // make sure our IO levels are in the right state

send_value = 0x00005c53;

int count = 0;

// uint32_t returned_value;

// while (1)

//{

while (count < 64000)

{

// returned_value =

trySPI(send_value); // call to assy lang to bit bang SPI

__delay_cycles(20000);

count++;

}

__delay_cycles(200000);

send_value = 0x0000a55a;

count = 0;

while (count < 64000)

{

trySPI(send_value); // call to assy lang to bit bang SPI

__delay_cycles(20000);

count++;

}

__delay_cycles(200000);

send_value = 0x00003333;

count = 0;

while (count < 64000)

{

trySPI(send_value); // call to assy lang to bit bang SPI

__delay_cycles(20000);

count++;

}

// }

//; down here we send the PRU to ARM closing event then do a halt

// now we can do the exit and halt

__R31 = PRU0_ARM_INTERRUPT; //35; // here we notify the ARM we are ready to quit

/* Halt the PRU core */

__halt();

return 0;

}

Here is the assembly: not done yet but getting close.

.asg "r4", SPI_TX ; these '.asg' are like the old defines in pasm

.asg "r2", LS_RX

.asg "r1", BIT ; don't mess with r3, we need this for the return

.global dumbdelay ; needs to be here so the extern into C will work

.align 4

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; this is a countdown loop to slow things down so I can use my old scope to see things working

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

dumbdelay:

; LDI32 r5, 59

LDI32 r5, 22

REPEAT?: SUB r5, r5, 1

QBNE REPEAT?, r5, 0

JMP R3.w2;

;DUMBDELAY: .macro

;; LDI32 r5, 59

; LDI32 r5, 22

;REPEAT?: SUB r5, r5, 1

; QBNE REPEAT?, r5, 0

; .endm

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; this does a single bit at a time, called 16 times from the send word macro below

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

.global spi_xfer_bit ; needs to be here so the extern into C will work

.align 4

spi_xfer_bit: ; .macro

LDI32 r1, 0x00001eb0

SBBO &r2, r1, 0, 48 ; save r2 through r13 at the start of this function

; DUMBDELAY ; slow things down

JAL r3.w2, ||dumbdelay|| ; slow things down

; Output LSPD control

QBBS MOSI_HIGH?, SPI_TX, BIT

clr r30.w0, r30.w0, 1 ;// Clear bit 1 This is MOSI

JMP MOSI_DONE?

MOSI_HIGH?:

set r30.w0, r30.w0, 1 ;// set bit 1 This is MOSI

NOP

MOSI_DONE?:

clr r30.w0, r30.w0, 0 ;// clr bit 0 This is SPI_SCLK

; Read LSPD - Set b0 of R11 to MISO

QBBC MISO_LOW?, R31.w0, 7 ; .asg This is MISO

SET LS_RX, LS_RX, BIT

JMP MISO_DONE?

MISO_LOW?: ; labels inside macros need the '?' character to build

NOP

MISO_DONE?:

JAL r3.w2, ||dumbdelay|| ; slow things down

set r30.w0, r30.w0, 0 ; set bit 0 This is SPI_SCLK

NOP

LDI32 r1, 0x00001eb0

LBBO &r2, r1, 0, 48 ; save r2 through r13 at the start of this function

JMP R3.w2;

;.endm

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; This macro calls the macro above for each bit

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

.global spi_xfer_word ; needs to be here so the extern into C will work

.align 4

spi_xfer_word: ;.macro

LDI32 r1, 0x00001db0 ; some place in my memory, figure these locations later

SBBO &r2, r1, 0, 48 ; save r2 through r13 at the start of this function

LDI32 BIT, 15 ; this LDI command is 5ns long