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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
Concepts and parts of this file have been contributed by Uladzimir Pylinsky
aka barthess.
*/
#include <stdlib.h>
#include "ch.h"
#include "hal.h"
/* buffers depth */
#define ACCEL_RX_DEPTH 6
#define ACCEL_TX_DEPTH 4
/* mma8451q specific addresses */
#define ACCEL_OUT_DATA 0x01
#define ACCEL_CTRL_REG1 0x2A
static uint8_t rxbuf[ACCEL_RX_DEPTH];
static uint8_t txbuf[ACCEL_TX_DEPTH];
static i2cflags_t errors = 0;
static int16_t acceleration_x, acceleration_y, acceleration_z;
#define mma8451_addr 0b0011100
/**
*
*/
static void print(char *p) {
while (*p) {
chIOPut(&SD2, *p++);
}
}
/**
*
*/
static void println(char *p) {
while (*p) {
chIOPut(&SD2, *p++);
}
chIOWriteTimeout(&SD2, (uint8_t *)"\r\n", 2, TIME_INFINITE);
}
/**
*
*/
static void printn(int16_t n) {
char buf[16], *p;
if (n > 0)
chIOPut(&SD2, '+');
else{
chIOPut(&SD2, '-');
n = abs(n);
}
if (!n)
chIOPut(&SD2, '0');
else {
p = buf;
while (n)
*p++ = (n % 10) + '0', n /= 10;
while (p > buf)
chIOPut(&SD2, *--p);
}
}
/**
* Converts data from 2complemented representation to signed integer
*/
int16_t complement2signed(uint8_t msb, uint8_t lsb){
uint16_t word = 0;
word = (msb << 8) + lsb;
if (msb > 0x7F){
return -1 * ((int16_t)((~word) + 1));
}
return (int16_t)word;
}
/*
* Application entry point.
*/
int main(void) {
msg_t status = RDY_OK;
/*
* System initializations.
* - HAL initialization, this also initializes the configured device drivers
* and performs the board-specific initializations.
* - Kernel initialization, the main() function becomes a thread and the
* RTOS is active.
*/
halInit();
chSysInit();
/*
* Prepares the Serial driver 2
*/
sdStart(&SD2, NULL); /* Default is 38400-8-N-1.*/
palSetPadMode(GPIOA, 2, PAL_MODE_ALTERNATE(7));
palSetPadMode(GPIOA, 3, PAL_MODE_ALTERNATE(7));
/* I2C interface #2 */
static const I2CConfig i2cfg2 = {
OPMODE_I2C,
400000,
FAST_DUTY_CYCLE_16_9,
};
i2cStart(&I2CD2, &i2cfg2);
/**
* Prepares the accelerometer
*/
txbuf[0] = ACCEL_CTRL_REG1; /* register address */
txbuf[1] = 0x1;
i2cAcquireBus(&I2CD2);
i2cMasterTransmitTimeout(&I2CD2, mma8451_addr, txbuf, 2, rxbuf, 0, TIME_INFINITE);
i2cReleaseBus(&I2CD2);
/*
* Normal main() thread activity, nothing in this test.
*/
while (TRUE) {
chThdSleepMilliseconds(100);
txbuf[0] = ACCEL_OUT_DATA; /* register address */
i2cAcquireBus(&I2CD2);
status = i2cMasterTransmitTimeout(&I2CD2, mma8451_addr, txbuf, 1, rxbuf, 6, TIME_INFINITE);
i2cReleaseBus(&I2CD2);
if (status != RDY_OK){
errors = i2cGetErrors(&I2CD2);
}
acceleration_x = complement2signed(rxbuf[0], rxbuf[1]);
acceleration_y = complement2signed(rxbuf[2], rxbuf[3]);
acceleration_z = complement2signed(rxbuf[4], rxbuf[5]);
print("x: ");
printn(acceleration_x);
print(" y: ");
printn(acceleration_y);
print(" z: ");
printn(acceleration_z);
println("");
}
}
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