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88 lines
2.4 KiB
88 lines
2.4 KiB
8 years ago
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/*
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Copyright 2017 Balz Guenat
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based on work by Jun Wako <wakojun@gmail.com>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "actuation_point.h"
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#include "i2c.h"
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///////////////////////////////////////////////////////////////////////////////
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//
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// AD5258 I2C digital potentiometer
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// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf
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//
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#define AD5258_ADDR 0b0011000
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#define AD5258_INST_RDAC 0x00
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#define AD5258_INST_EEPROM 0x20
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uint8_t read_rdac(void) {
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// read RDAC register
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i2c_start_write(AD5258_ADDR);
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i2c_master_write(AD5258_INST_RDAC);
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i2c_start_read(AD5258_ADDR);
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uint8_t ret = i2c_master_read(I2C_NACK);
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i2c_master_stop();
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return ret;
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};
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uint8_t read_eeprom(void) {
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i2c_start_write(AD5258_ADDR);
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i2c_master_write(AD5258_INST_EEPROM);
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i2c_start_read(AD5258_ADDR);
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uint8_t ret = i2c_master_read(I2C_NACK);
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i2c_master_stop();
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return ret;
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};
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void write_rdac(uint8_t rdac) {
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// write RDAC register:
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i2c_start_write(AD5258_ADDR);
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i2c_master_write(AD5258_INST_RDAC);
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i2c_master_write(rdac & 0x3F);
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i2c_master_stop();
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};
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void actuation_point_up(void) {
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// write RDAC register: lower value makes actuation point shallow
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uint8_t rdac = read_rdac();
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if (rdac == 0)
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write_rdac(0);
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else
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write_rdac(rdac-1);
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};
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void actuation_point_down(void) {
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// write RDAC register: higher value makes actuation point deep
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uint8_t rdac = read_rdac();
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if (rdac == 63)
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write_rdac(63);
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else
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write_rdac(rdac+1);
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};
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void adjust_actuation_point(int offset) {
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i2c_master_init();
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uint8_t rdac = read_eeprom() + offset;
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if (rdac > 63) { // protects from under and overflows
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if (offset > 0)
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write_rdac(63);
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else
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write_rdac(0);
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} else {
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write_rdac(rdac);
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}
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}
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