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Diffstat (limited to 'drivers/avr/i2c_slave.c')
-rw-r--r--drivers/avr/i2c_slave.c86
1 files changed, 0 insertions, 86 deletions
diff --git a/drivers/avr/i2c_slave.c b/drivers/avr/i2c_slave.c
deleted file mode 100644
index 62a378165..000000000
--- a/drivers/avr/i2c_slave.c
+++ /dev/null
@@ -1,86 +0,0 @@
1/* Copyright (C) 2019 Elia Ritterbusch
2 +
3 * This program is free software: you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation, either version 3 of the License, or
6 * (at your option) any later version.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <https://www.gnu.org/licenses/>.
15 */
16/* Library made by: g4lvanix
17 * GitHub repository: https://github.com/g4lvanix/I2C-slave-lib
18 */
19
20#include <avr/io.h>
21#include <util/twi.h>
22#include <avr/interrupt.h>
23#include <stdbool.h>
24
25#include "i2c_slave.h"
26
27volatile uint8_t i2c_slave_reg[I2C_SLAVE_REG_COUNT];
28
29static volatile uint8_t buffer_address;
30static volatile bool slave_has_register_set = false;
31
32void i2c_slave_init(uint8_t address) {
33 // load address into TWI address register
34 TWAR = address;
35 // set the TWCR to enable address matching and enable TWI, clear TWINT, enable TWI interrupt
36 TWCR = (1 << TWIE) | (1 << TWEA) | (1 << TWINT) | (1 << TWEN);
37}
38
39void i2c_slave_stop(void) {
40 // clear acknowledge and enable bits
41 TWCR &= ~((1 << TWEA) | (1 << TWEN));
42}
43
44ISR(TWI_vect) {
45 uint8_t ack = 1;
46
47 switch (TW_STATUS) {
48 case TW_SR_SLA_ACK:
49 // The device is now a slave receiver
50 slave_has_register_set = false;
51 break;
52
53 case TW_SR_DATA_ACK:
54 // This device is a slave receiver and has received data
55 // First byte is the location then the bytes will be writen in buffer with auto-incriment
56 if (!slave_has_register_set) {
57 buffer_address = TWDR;
58
59 if (buffer_address >= I2C_SLAVE_REG_COUNT) { // address out of bounds dont ack
60 ack = 0;
61 buffer_address = 0;
62 }
63 slave_has_register_set = true; // address has been receaved now fill in buffer
64 } else {
65 i2c_slave_reg[buffer_address] = TWDR;
66 buffer_address++;
67 }
68 break;
69
70 case TW_ST_SLA_ACK:
71 case TW_ST_DATA_ACK:
72 // This device is a slave transmitter and master has requested data
73 TWDR = i2c_slave_reg[buffer_address];
74 buffer_address++;
75 break;
76
77 case TW_BUS_ERROR:
78 // We got an error, reset i2c
79 TWCR = 0;
80 default:
81 break;
82 }
83
84 // Reset i2c state machine to be ready for next interrupt
85 TWCR |= (1 << TWIE) | (1 << TWINT) | (ack << TWEA) | (1 << TWEN);
86}