INTL 3:770/1 3:770/3
REPLYADDR tnp@invalid.invalid
REPLYTO 3:770/3.0 UUCP
MSGID: 27cf118c
REPLY: 51fa60dd
PID: SoupGate-Win32 v1.05
On 04/08/2024 21:13, Josef Möllers wrote:
> Hi,
>
> I used to use the sysfs interface to the GPIO pins (/sys/class/gpio) but
> I understand that is deprecated nowadays. So I tried to switch to lgpio
> which looks OK. However, I have problems writing and reading back pin
> states from different programs.
>
> My setup is as follows:
> I have a couple of relays (solid state and mechanical ones) that control
> various external devices.
> I use one program to switch devices on and off and want to use another
> program to read back the state of the device.
>
> Doing that with sysfs is easy:
> 1) export the pin:
> echo $pin > /sys/class/gpio/export
> echo $direction > /sys/class/gpio/gpio$pin/direction
> this needs to be done only once.
> 2) write the state of the pin, thus switching the device on/off:
> echo $newstate > /sys/class/gpio/gpio$pin/value
> this is done every time this is required
> 3) read back the state of the pin
> value=$( this is done every time I want to check the state of the device
>
> Now I switch a device on/off with lgpio as follows:
> 1) open the GPIO chip:
> h = lgGpiochipOpen(0);
> 2) claim the pin as an output:
> lgGpioClaimOutput(h, LG_SET_PULL_NONE, pin, value);
> which, to my understanding, already changes the pin's state?!?
> 3) write the new state
> lgGpioWrite(h, pin, value);
> 4) close the chip
> lgGpiochipClose(h);
>
> Reading back the state of the pin requires me to
> 1) open the GPIO chip:
> h = lgGpiochipOpen(0);
> 2) claim the pin as an input:
> lgGpioClaimInput(h, LG_SET_PULL_NONE, pin);
> 3) read back the pin's state
> lgGpioRead(h, pin);
> 4) close the chip
> lgGpiochipClose(h);
>
> However ... When I set the pin's state to "1", I still read back "0"!
>
> What am I doing wrong? Thanks in advance for any pointers.
>
> Josef
TLDR
Here is my C code to drive 4 relays from a Pi Zero W
Adpapted frim someone elses that also works
It works:
/* relays.h
2023-04-30
Public Domain */
/* zone 1-4, command ON or OFF */
/* All clever stuff is done in relayio, any call to this
* will initialise the hardware if it needs it. */
void relay(int zone, int command);
#define RELAY1 6
#define RELAY2 13
#define RELAY3 19
#define RELAY4 26
----------------------------------------------------------------
----------------------
/*
relayio.c
2023-04-30
Public Domain
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include "relays.h"
#define GPSET0 7
#define GPSET1 8
#define GPCLR0 10
#define GPCLR1 11
#define GPLEV0 13
#define GPLEV1 14
#define GPPUD 37
#define GPPUDCLK0 38
#define GPPUDCLK1 39
// port numbers for relays
unsigned piModel;
unsigned piRev;
static volatile uint32_t *gpioReg = MAP_FAILED;
#define PI_BANK (gpio>>5)
#define PI_BIT (1<<(gpio&0x1F))
/* gpio modes. */
#define PI_INPUT 0
#define PI_OUTPUT 1
#define PI_ALT0 4
#define PI_ALT1 5
#define PI_ALT2 6
#define PI_ALT3 7
#define PI_ALT4 3
#define PI_ALT5 2
static int initialized=0;
void gpioSetMode(unsigned gpio, unsigned mode)
{
int reg, shift;
reg=gpio/10;
shift=(gpio%10) * 3;
gpioReg[reg] = (gpioReg[reg] & ~(7<> shift) & 7;
}
/* Values for pull-ups/downs off, pull-down and pull-up. */
#define PI_PUD_OFF 0
#define PI_PUD_DOWN 1
#define PI_PUD_UP 2
void gpioSetPullUpDown(unsigned gpio, unsigned pud)
{
*(gpioReg + GPPUD) = pud;
usleep(20);
*(gpioReg + GPPUDCLK0 + PI_BANK) = PI_BIT;
usleep(20);
*(gpioReg + GPPUD) = 0;
*(gpioReg + GPPUDCLK0 + PI_BANK) = 0;
}
int gpioRead(unsigned gpio)
{
if ((*(gpioReg + GPLEV0 + PI_BANK) & PI_BIT) != 0)
return 1;
else
return 0;
}
void gpioWrite(unsigned gpio, unsigned level)
{
if (level == 0)
*(gpioReg + GPCLR0 + PI_BANK) = PI_BIT;
else
*(gpioReg + GPSET0 + PI_BANK) = PI_BIT;
}
void gpioTrigger(unsigned gpio, unsigned pulseLen, unsigned level)
{
if (level == 0)
*(gpioReg + GPCLR0 + PI_BANK) = PI_BIT;
else
*(gpioReg + GPSET0 + PI_BANK) = PI_BIT;
usleep(pulseLen);
if (level != 0) *(gpioReg + GPCLR0 + PI_BANK) = PI_BIT;
else
*(gpioReg + GPSET0 + PI_BANK) = PI_BIT;
}
/* Bit (1<Usenet Gateway (3:770/3)
SEEN-BY: 19/38 90/1 105/81 106/201 129/305 153/757 7715 218/700 840
SEEN-BY: 220/70 226/17 30 100 227/114 229/110 111 200 206 300 317
SEEN-BY: 229/400 426 428 470 550 616 664 700 266/512 267/800 282/1038
SEEN-BY: 291/111 292/854 310/31 320/219 322/757 342/200 396/45 460/58
SEEN-BY: 633/280 281 412 418 420 509 2744 712/848 770/1 3 100 330
SEEN-BY: 770/340 772/210 220 230 5020/400 5075/35
PATH: 770/3 1 633/280 229/426
|
