AMTS/Mieke/SW/ODD/bma.c

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/*
Demo program for the 2017/18 open door day at HTL Hollabrunn
Copyright (C) 2018 Andreas Mieke
This program 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.
This program 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 <https://www.gnu.org/licenses/>.
*/
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#include "bma.h"
#define BMA_ADDR (uint8_t)0x70 // 0b01110000
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// ---- Vendor address part
// --- User address part
// - Keep free for R/W bit (set by I2C_Send7bitAddress())
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void bma_init(void)
{
i2c1_init();
}
void bma_get_acc(uint8_t *X, uint8_t *Y, uint8_t *Z)
{
int16_t acc[3];
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// Send first register address to read
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I2C_GenerateSTART(I2C1, ENABLE);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
I2C_Send7bitAddress(I2C1, BMA_ADDR, I2C_Direction_Transmitter);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
I2C_SendData(I2C1, 0x02);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
I2C_GenerateSTOP(I2C1, ENABLE);
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// Start Rx transmission
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I2C_GenerateSTART(I2C1, ENABLE);
I2C_AcknowledgeConfig(I2C1, ENABLE);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
I2C_Send7bitAddress(I2C1, BMA_ADDR, I2C_Direction_Receiver);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
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// Read X LSB
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while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
acc[0] = (I2C_ReceiveData(I2C1) & 0xC0) >> 6;
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// Read X MSB
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while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
acc[0] = (I2C_ReceiveData(I2C1) & 0xFF) << 2 | (acc[0] & 0x0003);
if(acc[0] & 0x0200) acc[0] |= 0xFC00;
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// Read Y LSB
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while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
acc[1] = (I2C_ReceiveData(I2C1) & 0xC0) >> 6;
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// Read Y MSB
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while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
acc[1] = (I2C_ReceiveData(I2C1) & 0xFF) << 2 | (acc[1] & 0x0003);
if(acc[1] & 0x0200) acc[1] |= 0xFC00;
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// Read Z LSB
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while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
acc[2] = (I2C_ReceiveData(I2C1) & 0xC0) >> 6;
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// Read Z MSB
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I2C_AcknowledgeConfig(I2C1, DISABLE);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
acc[2] = (I2C_ReceiveData(I2C1) & 0xFF) << 2 | (acc[2] & 0x0003);
if(acc[2] & 0x0200) acc[2] |= 0xFC00;
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// Stop condition
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I2C_GenerateSTOP(I2C1, ENABLE);
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// Calculate display values, with a maximum amplitude of 2.0g, as described in the datasheet
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*X = (acc[0]/4) + 128;
*Y = (acc[1]/4) + 128;
*Z = (acc[2]/4) + 128;
}