libbcm2835

A tiny library for the BCM2835
git clone git://soophie.de/libbcm2835

Initial commit

commit: 4068f5468d8eb1a972b060aa2948c6ab63eb7e04
author: typable <contact@typable.dev>
time: 2024-06-10 11:40

4 file(s) changed, 219 insertion(s), 0 deletion(s)[browse files]

A Makefile
A README.md
A src/libbcm2835.c
A src/libbcm2835.h

Makefile [new file]

1default: build

3build:

4cc -o libbcm2835.so -shared -fPIC -Wall -Wextra -Werror -pedantic src/libbcm2835.c

6install:

7cc -o libbcm2835.so -shared -fPIC src/libbcm2835.c

8sudo cp src/libbcm2835.h /usr/local/include/libbcm2835.h

9sudo cp libbcm2835.so /usr/local/lib/libbcm2835.so

10sudo ldconfig

11rm libbcm2835.so

13uninstall:

14sudo rm /usr/local/include/libbcm2835.h

15sudo rm /usr/local/lib/libbcm2835.so

17clean:

18rm libbcm2835.so

README.md [new file]

1# libbcm2835

3A tiny library for the BCM2835

src/libbcm2835.c [new file]

1#include <stdio.h>
2#include <fcntl.h>
3#include <unistd.h>
4#include <sys/mman.h>
5
6#include "libbcm2835.h"
7
8static volatile u32_t *reg = MAP_FAILED;
9
10u32_t __bcm_bank(u32_t pin) {
11  return (pin >> 5);
12}
13
14int bcm_init(void) {
15  int fd = open("/dev/gpiomem", O_RDWR | O_SYNC);
16  if (fd < 0) {
17    fprintf(stderr, "Failed to open() /dev/gpiomem!\n");
18    return -1;
19  }
20  reg = (u32_t *) mmap(NULL, 0xB4, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
21  close(fd);
22  if (reg == MAP_FAILED) {
23    fprintf(stderr, "Bad, mmap() failed!\n");
24    return -1;
25  }
26  return 0;
27}
28
29void bcm_fsel(u32_t pin, bcm_fsel_e fsel) {
30  int idx = BCM_FSEL0 + (pin / 10);
31  int shift = 3 * (pin % 10);
32  reg[idx] = (reg[idx] & ~(7 << shift)) | (fsel << shift);
33}
34
35void bcm_set(u32_t pin) {
36  int idx = BCM_SET0 + __bcm_bank(pin);
37  reg[idx] = (1 << (pin & 0x1F));
38}
39
40void bcm_clr(u32_t pin) {
41  int idx = BCM_CLR0 + __bcm_bank(pin);
42  reg[idx] = (1 << (pin & 0x1F));
43}
44
45int bcm_lev(u32_t pin) {
46  int idx = BCM_LEV0 + __bcm_bank(pin);
47  return (reg[idx] & (1 << (pin & 0x1F))) != 0;
48}
49
50void bcm_pud(u32_t pin, bcm_pud_e pud) {
51  reg[BCM_PUD] = pud;
52  usleep(20);
53  reg[BCM_PUDCLK0 + __bcm_bank(pin)] = (1 << (pin & 0x1F));
54  usleep(20);
55  reg[BCM_PUD] = PUD_OFF;
56  reg[BCM_PUDCLK0 + __bcm_bank(pin)] = 0x00;
57}
58
59void bcm_write(u32_t pin, int level) {
60  level == HIGH
61    ? bcm_set(pin)
62    : bcm_clr(pin);
63}
64
65int bcm_read(u32_t pin) {
66  return bcm_lev(pin);
67}
68
69void bcm_pulse(u32_t pin, int level, u32_t sleep) {
70  level == HIGH
71    ? bcm_set(pin)
72    : bcm_clr(pin);
73  usleep(sleep);
74  level != HIGH
75    ? bcm_set(pin)
76    : bcm_clr(pin);
77}

src/libbcm2835.h [new file]

1/*
2BCM2835 ARM Peripherals
3
4Datasheet:
5https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
6
7
8      3V3 Power  *---[ 01 | 02 ]---*  5V Power
9    GPIO2 (SDA)  *---[ 03 | 04 ]---*  5V Power
10    GPIO3 (SCL)  *---[ 05 | 06 ]---*  Ground
11 GPIO4 (GPCLK0)  *---[ 07 | 08 ]---*  GPIO14 (TXD)
12         Ground  *---[ 09 | 10 ]---*  GPIO15 (RXD)
13         GPIO17  *---[ 11 | 12 ]---*  GPIO18 (PCM_CLK)
14         GPIO27  *---[ 13 | 14 ]---*  Ground
15         GPIO22  *---[ 15 | 16 ]---*  GPIO23
16      3V3 Power  *---[ 17 | 18 ]---*  GPIO24
17  GPIO10 (MOSI)  *---[ 19 | 20 ]---*  Ground
18   GPIO9 (MISO)  *---[ 21 | 22 ]---*  GPIO25
19  GPIO11 (SCLK)  *---[ 23 | 24 ]---*  GPIO8 (CE0)
20         Ground  *---[ 25 | 26 ]---*  GPIO7 (CE1)
21  GPIO0 (ID_SD)  *---[ 27 | 28 ]---*  GPIO1 (ID_SC)
22          GPIO5  *---[ 29 | 30 ]---*  Ground
23          GPIO6  *---[ 31 | 32 ]---*  GPIO12 (PWM0)
24  GPIO13 (PWM1)  *---[ 33 | 34 ]---*  Ground
25GPIO19 (PCM_FS)  *---[ 35 | 36 ]---*  GPIO16
26         GPIO26  *---[ 37 | 38 ]---*  GPIO20 (PCM_DIN)
27         Ground  *---[ 39 | 40 ]---*  GPIO21 (PCM_DOUT)
28
29
30gpiochip0 - 54 lines:
31
32---------------------   ---------------------   ---------------------
33line 00: ID_SDA         line 18: GPIO18         line 36: SD1_DATA0
34line 01: ID_SCL         line 19: GPIO19         line 37: SD1_DATA1
35line 02: GPIO2          line 20: GPIO20         line 38: SD1_DATA2
36line 03: GPIO3          line 21: GPIO21         line 39: SD1_DATA3
37line 04: GPIO4          line 22: GPIO22         line 40: PWM0_OUT
38line 05: GPIO5          line 23: GPIO23         line 41: PWM1_OUT
39line 06: GPIO6          line 24: GPIO24         line 42: ETH_CLK
40line 07: GPIO7          line 25: GPIO25         line 43: WIFI_CLK
41line 08: GPIO8          line 26: GPIO26         line 44: SDA0
42line 09: GPIO9          line 27: GPIO27         line 45: SCL0
43line 10: GPIO10         line 28: NC             line 46: SMPS_SCL
44line 11: GPIO11         line 29: LAN_RUN_BOOT   line 47: SMPS_SDA
45line 12: GPIO12         line 30: CTS0           line 48: SD_CLK_R
46line 13: GPIO13         line 31: RTS0           line 49: SD_CMD_R
47line 14: GPIO14         line 32: TXD0           line 50: SD_DATA0_R
48line 15: GPIO15         line 33: RXD0           line 51: SD_DATA1_R
49line 16: GPIO16         line 34: SD1_CLK        line 52: SD_DATA2_R
50line 17: GPIO17         line 35: SD1_CMD        line 53: SD_DATA3_R
51---------------------   ---------------------   ---------------------
52*/
53
54#ifndef BCM_2835_H
55#define BCM_2835_H
56
57#define BCM_FSEL0   0
58#define BCM_FSEL1   1
59#define BCM_FSEL2   2
60#define BCM_FSEL3   3
61#define BCM_FSEL4   4
62#define BCM_FSEL5   5
63#define BCM_SET0    7
64#define BCM_SET1    8
65#define BCM_CLR0    10
66#define BCM_CLR1    11
67#define BCM_LEV0    13
68#define BCM_LEV1    14
69#define BCM_EDS0    16
70#define BCM_EDS1    17
71#define BCM_REN0    19
72#define BCM_REN1    20
73#define BCM_FEN0    22
74#define BCM_FEN1    23
75#define BCM_HEN0    25
76#define BCM_HEN1    26
77#define BCM_LEN0    28
78#define BCM_LEN1    29
79#define BCM_AREN0   31
80#define BCM_AREN1   32
81#define BCM_AFEN0   34
82#define BCM_AFEN1   35
83#define BCM_PUD     37
84#define BCM_PUDCLK0 38
85#define BCM_PUDCLK1 39
86
87#define LOW  0
88#define HIGH 1
89
90typedef unsigned char u8_t;
91typedef unsigned int u32_t;
92
93typedef enum {
94  FSEL_IN   = 0x00,
95  FSEL_OUT  = 0x01,
96  FSEL_ALT0 = 0x04,
97  FSEL_ALT1 = 0x05,
98  FSEL_ALT2 = 0x06,
99  FSEL_ALT3 = 0x07,
100  FSEL_ALT4 = 0x03,
101  FSEL_ALT5 = 0x02,
102} bcm_fsel_e;
103
104typedef enum {
105  PUD_OFF  = 0x00,
106  PUD_DOWN = 0x01,
107  PUD_UP   = 0x02,
108} bcm_pud_e;
109
110int bcm_init(void);
111void bcm_fsel(u32_t pin, bcm_fsel_e fsel);
112void bcm_set(u32_t pin);
113void bcm_clr(u32_t pin);
114int bcm_lev(u32_t pin);
115void bcm_pud(u32_t pin, bcm_pud_e pud);
116
117void bcm_write(u32_t pin, int level);
118int bcm_read(u32_t pin);
119void bcm_pulse(u32_t pin, int level, u32_t sleep);
120
121#endif

so://phie

libbcm2835

Initial commit