Thank you very much for your answer to Chad,
I've tried this piece of code:
Arm side:
#define DDR_BASEADDR 0x10000
#define OFFSET_DDR 0x00
int main(int argc, char **argv)
{
int mem_fd = open("/dev/mem", O_RDWR | O_SYNC);
if (mem_fd == -1){
printf("Err");
return 0;
}
volatile void *ddrMapp = NULL;
volatile void *DDR_regaddr1 = NULL;
ddrMapp = mmap(0, 0x0FFFFFFF, PROT_WRITE | PROT_READ, MAP_SHARED, mem_fd,
DDR_BASEADDR);
DDR_regaddr1 = ddrMapp + OFFSET_DDR;
printf("PRU address: %X\n", &DDR_regaddr1);
return(0);
}
PRU side:
#include <stdint.h>
#include <pru_cfg.h>
#include "resource_table_empty.h"
#define PRU_SHARED_MEM_ADDR 0x00010000
void main(void)
{
// enable OCP
CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;
volatile int* buffer = (volatile int *) PRU_SHARED_MEM_ADDR;
buffer[0] = 0xED;
/* Clear SYSCFG[STANDBY_INIT] to enable OCP master port --> Shared memory
*/
CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;
}
And the value returned from the printf is 0xBEFFFAFC , rather than
0x000000ED. Maybe I am pointing to the wrong physical address, do you know
what am I doing wrong here?
Thank you very much,
Fred Gomes
Chad Baker <cmbak...@gmail.com> escreveu no dia quarta, 21/11/2018 à(s)
16:55:
> On the C-side, you need to find the address that maps the physical to
> logical address. The function "mmap" does that.
> volatile int *buffer = (volatile int *)mmao( PRU_SHARED_ADDRESS, ...
> Check the man pages for how to use mmap.
> Chad
>
> On 11/21/18 7:47 AM, Fred Gomes wrote:
>
> Can anyone explain to me why the below example does not work? I could
> confirm on the PRU side that I am writing correctly in the 0x10000 address,
> however, I can't get the written value in the beagle bone side. It's quite
> confusing to me, since if the memory is shared it should work.
>
> PRU code:
>
> #include <stdint.h>
> #include <pru_cfg.h>
> #include "resource_table_empty.h"
>
> #define PRU_SHARED_MEM_ADDR 0x00010000
>
> void main(void)
> {
> // enable OCP
> CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;
> volatile int* buffer = (volatile int *) PRU_SHARED_MEM_ADDR;
> buffer[0] = 0xED;
> /* Clear SYSCFG[STANDBY_INIT] to enable OCP master port --> Shared memory
> */
> CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;
> }
>
> Host C++ code:
>
> #include <unistd.h>
> #include <stdio.h>
> #include <inttypes.h>
> #include <prussdrv.h>
> #include <pruss_intc_mapping.h>
>
> using namespace std;
>
> #define PRU_SHARED_MEM_ADDR 0x00010000
>
> int main(int argc, char **argv)
> {
>
> volatile int* buffer = (volatile int *)PRU_SHARED_MEM_ADDR;
>
>
> printf("Memory address: %x\n", &buffer);
>
> return(0);
> }
>
> Regards,
> Fred Gomes
>
> <fred.p.gome...@gmail.com> escreveu no dia terça, 20/11/2018 à(s) 17:13:
>
>> Hi,
>>
>> I need your help,
>>
>> I am developing an application on the beagle bone for reading data for an
>> SPI slave. For that, I have to use the PRU since the data transmission is
>> up to 15 KHz.
>>
>> Following this tutorial: https://markayoder.github.io/PRUCookbook/ , in
>> the *Chapter** 5 - Memory allocation*, it is explained how memory
>> allocation works on the PRU, as well as how to store variables on specific
>> memory addresses. But he doesn't mention how do I get access to those
>> memory addresses from a host code.
>>
>> I did some researching on the internet and everything I can find is
>> examples of getting access to specific memory adresses using the prussdrv,
>> which I think no longer work in the latest Debian images ( I tried to use
>> it and it trhowed an error from the very beginning when trying to open the
>> drive (*prussdrv_open()*) . Can anyone give me an inkling on how can I
>> achieve this?
>>
>>
>> Ps: Here's an example using the prussdrv :
>> http://catch22.eu/beaglebone/beaglebone-pru-ipc/
>>
>> Best regards,
>> Fred Gomes
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