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/*
Copyright 2017 Balz Guenat
based on work by Jun Wako <wakojun@gmail.com>
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 2 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 <http://www.gnu.org/licenses/>.
*/
#include "actuation_point.h"
#include "i2c.h"
///////////////////////////////////////////////////////////////////////////////
//
// AD5258 I2C digital potentiometer
// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf
//
#define AD5258_ADDR 0b0011000
#define AD5258_INST_RDAC 0x00
#define AD5258_INST_EEPROM 0x20
uint8_t read_rdac(void) {
// read RDAC register
i2c_start_write(AD5258_ADDR);
i2c_master_write(AD5258_INST_RDAC);
i2c_start_read(AD5258_ADDR);
uint8_t ret = i2c_master_read(I2C_NACK);
i2c_master_stop();
return ret;
};
uint8_t read_eeprom(void) {
i2c_start_write(AD5258_ADDR);
i2c_master_write(AD5258_INST_EEPROM);
i2c_start_read(AD5258_ADDR);
uint8_t ret = i2c_master_read(I2C_NACK);
i2c_master_stop();
return ret;
};
void write_rdac(uint8_t rdac) {
// write RDAC register:
i2c_start_write(AD5258_ADDR);
i2c_master_write(AD5258_INST_RDAC);
i2c_master_write(rdac & 0x3F);
i2c_master_stop();
};
void actuation_point_up(void) {
// write RDAC register: lower value makes actuation point shallow
uint8_t rdac = read_rdac();
if (rdac == 0)
write_rdac(0);
else
write_rdac(rdac-1);
};
void actuation_point_down(void) {
// write RDAC register: higher value makes actuation point deep
uint8_t rdac = read_rdac();
if (rdac == 63)
write_rdac(63);
else
write_rdac(rdac+1);
};
void adjust_actuation_point(int offset) {
i2c_master_init();
uint8_t rdac = read_eeprom() + offset;
if (rdac > 63) { // protects from under and overflows
if (offset > 0)
write_rdac(63);
else
write_rdac(0);
} else {
write_rdac(rdac);
}
}
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