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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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