diff options
Diffstat (limited to 'quantum/split_common/i2c.c')
-rw-r--r-- | quantum/split_common/i2c.c | 184 |
1 files changed, 0 insertions, 184 deletions
diff --git a/quantum/split_common/i2c.c b/quantum/split_common/i2c.c deleted file mode 100644 index 45e958b39..000000000 --- a/quantum/split_common/i2c.c +++ /dev/null | |||
@@ -1,184 +0,0 @@ | |||
1 | #include <util/twi.h> | ||
2 | #include <avr/io.h> | ||
3 | #include <stdlib.h> | ||
4 | #include <avr/interrupt.h> | ||
5 | #include <util/twi.h> | ||
6 | #include <stdbool.h> | ||
7 | #include "i2c.h" | ||
8 | #include "split_flags.h" | ||
9 | |||
10 | // Limits the amount of we wait for any one i2c transaction. | ||
11 | // Since were running SCL line 100kHz (=> 10μs/bit), and each transactions is | ||
12 | // 9 bits, a single transaction will take around 90μs to complete. | ||
13 | // | ||
14 | // (F_CPU/SCL_CLOCK) => # of μC cycles to transfer a bit | ||
15 | // poll loop takes at least 8 clock cycles to execute | ||
16 | #define I2C_LOOP_TIMEOUT (9+1)*(F_CPU/SCL_CLOCK)/8 | ||
17 | |||
18 | #define BUFFER_POS_INC() (slave_buffer_pos = (slave_buffer_pos+1)%SLAVE_BUFFER_SIZE) | ||
19 | |||
20 | volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE]; | ||
21 | |||
22 | static volatile uint8_t slave_buffer_pos; | ||
23 | static volatile bool slave_has_register_set = false; | ||
24 | |||
25 | // Wait for an i2c operation to finish | ||
26 | inline static | ||
27 | void i2c_delay(void) { | ||
28 | uint16_t lim = 0; | ||
29 | while(!(TWCR & (1<<TWINT)) && lim < I2C_LOOP_TIMEOUT) | ||
30 | lim++; | ||
31 | |||
32 | // easier way, but will wait slightly longer | ||
33 | // _delay_us(100); | ||
34 | } | ||
35 | |||
36 | // Setup twi to run at 100kHz | ||
37 | void i2c_master_init(void) { | ||
38 | // no prescaler | ||
39 | TWSR = 0; | ||
40 | // Set TWI clock frequency to SCL_CLOCK. Need TWBR>10. | ||
41 | // Check datasheets for more info. | ||
42 | TWBR = ((F_CPU/SCL_CLOCK)-16)/2; | ||
43 | } | ||
44 | |||
45 | // Start a transaction with the given i2c slave address. The direction of the | ||
46 | // transfer is set with I2C_READ and I2C_WRITE. | ||
47 | // returns: 0 => success | ||
48 | // 1 => error | ||
49 | uint8_t i2c_master_start(uint8_t address) { | ||
50 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTA); | ||
51 | |||
52 | i2c_delay(); | ||
53 | |||
54 | // check that we started successfully | ||
55 | if ( (TW_STATUS != TW_START) && (TW_STATUS != TW_REP_START)) | ||
56 | return 1; | ||
57 | |||
58 | TWDR = address; | ||
59 | TWCR = (1<<TWINT) | (1<<TWEN); | ||
60 | |||
61 | i2c_delay(); | ||
62 | |||
63 | if ( (TW_STATUS != TW_MT_SLA_ACK) && (TW_STATUS != TW_MR_SLA_ACK) ) | ||
64 | return 1; // slave did not acknowledge | ||
65 | else | ||
66 | return 0; // success | ||
67 | } | ||
68 | |||
69 | |||
70 | // Finish the i2c transaction. | ||
71 | void i2c_master_stop(void) { | ||
72 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO); | ||
73 | |||
74 | uint16_t lim = 0; | ||
75 | while(!(TWCR & (1<<TWSTO)) && lim < I2C_LOOP_TIMEOUT) | ||
76 | lim++; | ||
77 | } | ||
78 | |||
79 | // Write one byte to the i2c slave. | ||
80 | // returns 0 => slave ACK | ||
81 | // 1 => slave NACK | ||
82 | uint8_t i2c_master_write(uint8_t data) { | ||
83 | TWDR = data; | ||
84 | TWCR = (1<<TWINT) | (1<<TWEN); | ||
85 | |||
86 | i2c_delay(); | ||
87 | |||
88 | // check if the slave acknowledged us | ||
89 | return (TW_STATUS == TW_MT_DATA_ACK) ? 0 : 1; | ||
90 | } | ||
91 | |||
92 | uint8_t i2c_master_write_data(void *const TXdata, uint8_t dataLen) { | ||
93 | |||
94 | uint8_t *data = (uint8_t *)TXdata; | ||
95 | int err = 0; | ||
96 | |||
97 | for (int i = 0; i < dataLen; i++) { | ||
98 | err = i2c_master_write(data[i]); | ||
99 | |||
100 | if ( err ) | ||
101 | return err; | ||
102 | } | ||
103 | |||
104 | return err; | ||
105 | |||
106 | } | ||
107 | |||
108 | // Read one byte from the i2c slave. If ack=1 the slave is acknowledged, | ||
109 | // if ack=0 the acknowledge bit is not set. | ||
110 | // returns: byte read from i2c device | ||
111 | uint8_t i2c_master_read(int ack) { | ||
112 | TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA); | ||
113 | |||
114 | i2c_delay(); | ||
115 | return TWDR; | ||
116 | } | ||
117 | |||
118 | void i2c_reset_state(void) { | ||
119 | TWCR = 0; | ||
120 | } | ||
121 | |||
122 | void i2c_slave_init(uint8_t address) { | ||
123 | TWAR = address << 0; // slave i2c address | ||
124 | // TWEN - twi enable | ||
125 | // TWEA - enable address acknowledgement | ||
126 | // TWINT - twi interrupt flag | ||
127 | // TWIE - enable the twi interrupt | ||
128 | TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN); | ||
129 | } | ||
130 | |||
131 | ISR(TWI_vect); | ||
132 | |||
133 | ISR(TWI_vect) { | ||
134 | uint8_t ack = 1; | ||
135 | switch(TW_STATUS) { | ||
136 | case TW_SR_SLA_ACK: | ||
137 | // this device has been addressed as a slave receiver | ||
138 | slave_has_register_set = false; | ||
139 | break; | ||
140 | |||
141 | case TW_SR_DATA_ACK: | ||
142 | // this device has received data as a slave receiver | ||
143 | // The first byte that we receive in this transaction sets the location | ||
144 | // of the read/write location of the slaves memory that it exposes over | ||
145 | // i2c. After that, bytes will be written at slave_buffer_pos, incrementing | ||
146 | // slave_buffer_pos after each write. | ||
147 | if(!slave_has_register_set) { | ||
148 | slave_buffer_pos = TWDR; | ||
149 | // don't acknowledge the master if this memory loctaion is out of bounds | ||
150 | if ( slave_buffer_pos >= SLAVE_BUFFER_SIZE ) { | ||
151 | ack = 0; | ||
152 | slave_buffer_pos = 0; | ||
153 | } | ||
154 | |||
155 | slave_has_register_set = true; | ||
156 | } else { | ||
157 | i2c_slave_buffer[slave_buffer_pos] = TWDR; | ||
158 | |||
159 | if ( slave_buffer_pos == I2C_BACKLIT_START) { | ||
160 | BACKLIT_DIRTY = true; | ||
161 | } else if ( slave_buffer_pos == (I2C_RGB_START+3)) { | ||
162 | RGB_DIRTY = true; | ||
163 | } | ||
164 | |||
165 | BUFFER_POS_INC(); | ||
166 | } | ||
167 | break; | ||
168 | |||
169 | case TW_ST_SLA_ACK: | ||
170 | case TW_ST_DATA_ACK: | ||
171 | // master has addressed this device as a slave transmitter and is | ||
172 | // requesting data. | ||
173 | TWDR = i2c_slave_buffer[slave_buffer_pos]; | ||
174 | BUFFER_POS_INC(); | ||
175 | break; | ||
176 | |||
177 | case TW_BUS_ERROR: // something went wrong, reset twi state | ||
178 | TWCR = 0; | ||
179 | default: | ||
180 | break; | ||
181 | } | ||
182 | // Reset everything, so we are ready for the next TWI interrupt | ||
183 | TWCR |= (1<<TWIE) | (1<<TWINT) | (ack<<TWEA) | (1<<TWEN); | ||
184 | } | ||