279 lines
9.2 KiB
C
279 lines
9.2 KiB
C
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/*******************************************************************************
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*
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* i2c.c
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*
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* Copyright (c) 2013 Shahrooz Shahparnia (sshahrooz@gmail.com)
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*
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* Description:
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* i2c is a command-line utility for executing i2c commands with the
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* Broadcom bcm2835. It was developed and tested on a Raspberry Pi single-board
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* computer model B. The utility is based on the bcm2835 C library developed
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* by Mike McCauley of Open System Consultants, http://www.open.com.au/mikem/bcm2835/.
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*
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* Invoking spincl results in a read or write I2C transfer. Options include the
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* the I2C clock frequency, read/write, address, and port initialization/closing
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* procedures. The command usage and command-line parameters are described below
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* in the showusage function, which prints the usage if no command-line parameters
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* are included or if there are any command-line parameter errors. Invoking i2c
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* requires root privilege.
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*
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* This file contains the main function as well as functions for displaying
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* usage and for parsing the command line.
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*
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* Open Source Licensing GNU GPLv3
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*
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* Building:
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* After installing bcm2835, you can build this
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* with something like:
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* gcc -o i2c i2c.c -l bcm2835
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* sudo ./i2c
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*
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* Or you can test it before installing with:
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* gcc -o i2c -I ../../src ../../src/bcm2835.c i2c.c
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* sudo ./i2c
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*
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* History:
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* 11/05 VERSION 1.0.0: Original
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*
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* User input parsing (comparse) and showusage\
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* have been adapted from: http://ipsolutionscorp.com/raspberry-pi-spi-utility/
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* mostly to keep consistence with the spincl tool usage.
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*
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* Compile with: gcc -o i2c i2c.c bcm2835.c
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*
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* Examples:
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*
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* Set up ADC (Arduino: ADC1015)
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* sudo ./i2c -s72 -dw -ib 3 0x01 0x44 0x00 (select config register, setup mux, etc.)
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* sudo ./i2c -s72 -dw -ib 1 0x00 (select ADC data register)
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*
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* Bias DAC (Arduino: MCP4725) at some voltage
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* sudo ./i2c -s99 -dw -ib 3 0x60 0x7F 0xF0 (FS output is with 0xFF 0xF0)
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* Read ADC convergence result
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* sudo ./i2c -s72 -dr -ib 2 (FS output is 0x7FF0 with PGA1 = 1)
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*
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* In a DAC to ADC loop back typical results are:
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*
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* DAC VOUT ADC
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* 7FFh 1.6V 677h Note ratio is FS_ADC*PGA_GAIN/FS_DAC = 4.096/3.3 = 1.23
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* 5FFh 1.2V 4DCh
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* 8F0h 1.8V 745h
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* 9D0h 2V 7EAh
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* 000h 10mV 004h
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*
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********************************************************************************/
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#include <bcm2835.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdint.h>
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#define MODE_READ 0
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#define MODE_WRITE 1
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#define MAX_LEN 32
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char wbuf[MAX_LEN];
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typedef enum {
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NO_ACTION,
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I2C_BEGIN,
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I2C_END
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} i2c_init;
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uint8_t init = NO_ACTION;
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uint16_t clk_div = BCM2835_I2C_CLOCK_DIVIDER_148;
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uint8_t slave_address = 0x00;
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uint32_t len = 0;
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uint8_t mode = MODE_READ;
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//*******************************************************************************
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// comparse: Parse the command line and return EXIT_SUCCESS or EXIT_FAILURE
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// argc: number of command-line arguments
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// argv: array of command-line argument strings
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//*******************************************************************************
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int comparse(int argc, char **argv) {
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int argnum, i, xmitnum;
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if (argc < 2) { // must have at least program name and len arguments
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// or -ie (I2C_END) or -ib (I2C_BEGIN)
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fprintf(stderr, "Insufficient command line arguments\n");
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return EXIT_FAILURE;
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}
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argnum = 1;
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while (argnum < argc && argv[argnum][0] == '-') {
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switch (argv[argnum][1]) {
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case 'i': // I2C init
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switch (argv[argnum][2]) {
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case 'b': init = I2C_BEGIN; break;
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case 'e': init = I2C_END; break;
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default:
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fprintf(stderr, "%c is not a valid init option\n", argv[argnum][2]);
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return EXIT_FAILURE;
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}
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break;
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case 'd': // Read/Write Mode
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switch (argv[argnum][2]) {
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case 'r': mode = MODE_READ; break;
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case 'w': mode = MODE_WRITE; break;
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default:
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fprintf(stderr, "%c is not a valid init option\n", argv[argnum][2]);
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return EXIT_FAILURE;
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}
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break;
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case 'c': // Clock divider
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clk_div = atoi(argv[argnum]+2);
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break;
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case 's': // Slave address
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slave_address = atoi(argv[argnum]+2);
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break;
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default:
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fprintf(stderr, "%c is not a valid option\n", argv[argnum][1]);
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return EXIT_FAILURE;
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}
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argnum++; // advance the argument number
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}
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// If command is used for I2C_END or I2C_BEGIN only
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if (argnum == argc && init != NO_ACTION) // no further arguments are needed
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return EXIT_SUCCESS;
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// Get len
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if (strspn(argv[argnum], "0123456789") != strlen(argv[argnum])) {
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fprintf(stderr, "Invalid number of bytes specified\n");
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return EXIT_FAILURE;
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}
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len = atoi(argv[argnum]);
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if (len > MAX_LEN) {
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fprintf(stderr, "Invalid number of bytes specified\n");
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return EXIT_FAILURE;
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}
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argnum++; // advance the argument number
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xmitnum = argc - argnum; // number of xmit bytes
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memset(wbuf, 0, sizeof(wbuf));
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for (i = 0; i < xmitnum; i++) {
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if (strspn(argv[argnum + i], "0123456789abcdefABCDEFxX") != strlen(argv[argnum + i])) {
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fprintf(stderr, "Invalid data: ");
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fprintf(stderr, "%d \n", xmitnum);
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return EXIT_FAILURE;
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}
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wbuf[i] = (char)strtoul(argv[argnum + i], NULL, 0);
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}
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return EXIT_SUCCESS;
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}
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//*******************************************************************************
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// showusage: Print the usage statement and return errcode.
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//*******************************************************************************
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int showusage(int errcode) {
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printf("i2c \n");
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printf("Usage: \n");
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printf(" i2c [options] len [rcv/xmit bytes]\n");
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printf("\n");
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printf(" Invoking i2c results in an I2C transfer of a specified\n");
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printf(" number of bytes. Additionally, it can be used to set the appropriate\n");
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printf(" GPIO pins to their respective I2C configurations or return them\n");
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printf(" to GPIO input configuration. Options include the I2C clock frequency,\n");
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printf(" initialization option (i2c_begin and i2c_end). i2c must be invoked\n");
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printf(" with root privileges.\n");
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printf("\n");
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printf(" The following are the options, which must be a single letter\n");
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printf(" preceded by a '-' and followed by another character.\n");
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printf(" -dx where x is 'w' for write and 'r' is for read.\n");
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printf(" -ix where x is the I2C init option, b[egin] or e[nd]\n");
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printf(" The begin option must be executed before any transfer can happen.\n");
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printf(" It may be included with a transfer.\n");
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printf(" The end option will return the I2C pins to GPIO inputs.\n");
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printf(" It may be included with a transfer.\n");
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printf(" -cx where x is the clock divider from 250MHz. Allowed values\n");
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printf(" are 150 through 2500.\n");
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printf(" Corresponding frequencies are specified in bcm2835.h.\n");
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printf("\n");
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printf(" len: The number of bytes to be transmitted or received.\n");
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printf(" The maximum number of bytes allowed is %d\n", MAX_LEN);
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printf("\n");
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printf("\n");
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printf("\n");
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return errcode;
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}
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char buf[MAX_LEN];
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int i;
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uint8_t data;
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int main(int argc, char **argv) {
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printf("Running ... \n");
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// parse the command line
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if (comparse(argc, argv) == EXIT_FAILURE) return showusage (EXIT_FAILURE);
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if (!bcm2835_init())
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{
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printf("bcm2835_init failed. Are you running as root??\n");
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return 1;
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}
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// I2C begin if specified
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if (init == I2C_BEGIN)
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{
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if (!bcm2835_i2c_begin())
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{
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printf("bcm2835_i2c_begin failed. Are you running as root??\n");
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return 1;
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}
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}
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// If len is 0, no need to continue, but do I2C end if specified
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if (len == 0) {
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if (init == I2C_END) bcm2835_i2c_end();
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printf("... done!\n");
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return EXIT_SUCCESS;
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}
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bcm2835_i2c_setSlaveAddress(slave_address);
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bcm2835_i2c_setClockDivider(clk_div);
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fprintf(stderr, "Clock divider set to: %d\n", clk_div);
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fprintf(stderr, "len set to: %d\n", len);
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fprintf(stderr, "Slave address set to: %d\n", slave_address);
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if (mode == MODE_READ) {
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for (i=0; i<MAX_LEN; i++) buf[i] = 'n';
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data = bcm2835_i2c_read(buf, len);
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printf("Read Result = %d\n", data);
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for (i=0; i<MAX_LEN; i++) {
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if(buf[i] != 'n') printf("Read Buf[%d] = %x\n", i, buf[i]);
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}
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}
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if (mode == MODE_WRITE) {
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data = bcm2835_i2c_write(wbuf, len);
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printf("Write Result = %d\n", data);
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}
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// This I2C end is done after a transfer if specified
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if (init == I2C_END) bcm2835_i2c_end();
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bcm2835_close();
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printf("... done!\n");
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return 0;
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}
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