Wow. This is great. I like the problem/solution format. It really makes it easy
to see which sections you might be interested in reading.
There is a typo on the first line of the Case Studies - Introduction that jumps out
though: "It’s an excisting time"
And I wouldn't mind seeing a bit more of an explanation about how rpmsg works,
for example a listing of resource_table_0.h with an explanation.
On 08/17/2018 09:58 AM, Mark A. Yoder wrote:
The PRU cookbook is nearing completion (more accurately, I'm running out of
summer).
Here's a link https://markayoder.github.io/PRUCookbook/
I'm happy for any feedback you can give me.
--Mark
On Thursday, June 28, 2018 at 8:45:00 PM UTC-4, Neilh wrote:
Ok thanks. I see I was think SHARED_RAM between the ARM-A8 and PRU0 and its
actually shared between ARM PRU0 and PRU1. Ahhhh-lightbulb---hhhhh
Many thanks for the evolving cookbook and detailed explanation- I have got
a little lost at times digging through the manual - gosh I want to read all the
PRU sections - I'd have paid gold 4weeks ago when I started using the PRUst!.
If it becomes a book I'll be first in line to buy it :).
The PRUs are a cool part of the BBB - and now I've got it working appears
pretty simple.
On Thu, Jun 28, 2018 at 12:59 PM Mark A. Yoder <mark.a...@gmail.com
<javascript:>> wrote:
Neilh:
I've worked up some examples[1] for a PRU Cookbook that might help.
I'm taking a similar approach to what you did, but I'm using DRAM0. It
shouldn't be hard
to switch to shared RAM.
--Mark
[1]
https://markayoder.github.io/PRUCookbook/05blocks/blocks.html#_controlling_the_pwm_frequency
<https://markayoder.github.io/PRUCookbook/05blocks/blocks.html#_controlling_the_pwm_frequency>
On Wednesday, June 27, 2018 at 5:36:13 PM UTC-4, Neilh wrote:
Oops I got it - it was sizing a pointer and not the struct.
I'd be interested in anybody's comments on the use of the SHAREDRAM
approach as it makes for a very simple one way api. I'm partly publishing this
as a tutorial for anybody else - but its my first try at the PRU.
Here is the logic anlayzer output from the Saleae 8 Channels
mapping of PRU0 to GPIO P9_25 ...P8_12
There is an increasing pulse count chn0, and then fixed 1hz, 2hz...
on subsequent channels
On Wed, Jun 27, 2018 at 2:13 PM Neil Hancock <neilh...@gmail.com>
wrote:
Oops - you are right, I'll update my comments
Here is the code that is allocating the SHAREDRAM - though I'm
still hazy as to how mmap() works in BBB mapping the SHAREDRAM
#define AM33XX_DATARAM0_PHYS_BASE0x4a300000
#define AM33XX_DATARAM1_PHYS_BASE0x4a302000
#define AM33XX_PRUSS_SHAREDRAM_BASE0x4a310000
#define SHARED_RAM_SZ 16 /* grab 8*4 bytes or 8 words */
volatile uint16_t *shared_dataram;
/* Define an API to be calleable from JS -still needs work */
void bbbio_ppm_api(struct channels_s *channels){
memcpy((void *)shared_dataram,(void
*)channels,sizeof(channels));
}
void bbbio_ppm_init() {
/* Allocate shared memory pointer to PRU0 DATARAM */
int mem_dev = open("/dev/mem", O_RDWR | O_SYNC);
volatile void *shared_dataram_init = mmap(NULL,
SHARED_RAM_SZ,
PROT_READ | PROT_WRITE,
MAP_SHARED,
mem_dev,
AM33XX_PRUSS_SHAREDRAM_BASE
);
shared_dataram = (uint16_t *) shared_dataram_init;
}
void bbbio_ppm_cleanup() {
munmap((void *)shared_dataram,SHARED_RAM_SZ); //njh guess at
releasing it.
}
#ifdef MAIN_LOCAL
void main() {
unsigned int sec_i, chnl_j;
unsigned int offset;
struct channels_s channels;
volatile uint16_t *shared_dataram2;
bbbio_ppm_init();
uint16_t ppm =60;//actually
offset = 0;
channels.chn[offset].sr =ppm;
printf("shared_datara2 = %p, offset=%d At init Read:",
shared_dataram,offset);
shared_dataram2 = (uint16_t *) shared_dataram;
for(chnl_j=0; chnl_j<8; chnl_j++) {
printf(" %04d", *shared_dataram2);
shared_dataram2++;
if (0x3 ==(chnl_j & 0x3)){printf(" ");}
}
printf("\n");
ppm =0;
for(chnl_j=0; chnl_j<8; chnl_j++) {
channels.chn[chnl_j].sr=ppm;
ppm += 60;
}
//Fut - wait for ack from PRU and then init shared ram
//while (1)
{
ppm=60;
for(sec_i=0; sec_i<8; sec_i++) {
channels.chn[offset].sr +=ppm;
//memcpy((void *)shared_dataram,(void
*)&channels,sizeof(channels));
bbbio_ppm_api(&channels);
printf("Writing %04d Read:", ppm);
shared_dataram2 = (uint16_t *) shared_dataram;
for(chnl_j=0; chnl_j<8; chnl_j++) {
printf(" %04d", *shared_dataram2);
shared_dataram2++;
if (0x3 ==(chnl_j & 0x3)){printf(" ");}
}
printf("\n");
sleep(1);
}
}
bbbio_ppm_cleanup();
}
#endif //MAIN_LOCAL
On Wed, Jun 27, 2018 at 1:33 PM Dennis Lee Bieber
<wlf...@ix.netcom.com> wrote:
On Wed, 27 Jun 2018 12:18:27 -0700, Neil Hancock
<neilh...@gmail.com> declaimed the
following:
> with 8*int16 (or 32bytes).
>
Pardon?
int16 is 2-bytes, 8*2 => 16 bytes
>Initially I tried 8*int32 (64bytes) but could only
sucessfully use the
>first 5*int32(40bytes
>
Similarly, int32 is 4-bytes, 8*4 => 32; 5*4 => 20
--
Wulfraed Dennis Lee Bieber AF6VN
wlf...@ix.netcom.com HTTP://wlfraed.home.netcom.com/
<HTTP://wlfraed.home.netcom.com/>
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