aboutsummaryrefslogtreecommitdiff
path: root/keyboards/sx60/twimaster.c
diff options
context:
space:
mode:
Diffstat (limited to 'keyboards/sx60/twimaster.c')
-rw-r--r--keyboards/sx60/twimaster.c207
1 files changed, 0 insertions, 207 deletions
diff --git a/keyboards/sx60/twimaster.c b/keyboards/sx60/twimaster.c
deleted file mode 100644
index 30d8c24bf..000000000
--- a/keyboards/sx60/twimaster.c
+++ /dev/null
@@ -1,207 +0,0 @@
1/*************************************************************************
2* Title: I2C master library using hardware TWI interface
3* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
4* File: $Id: twimaster.c,v 1.3 2005/07/02 11:14:21 Peter Exp $
5* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
6* Target: any AVR device with hardware TWI
7* Usage: API compatible with I2C Software Library i2cmaster.h
8**************************************************************************/
9#include <inttypes.h>
10#include <compat/twi.h>
11
12#include <i2cmaster.h>
13
14/* define CPU frequency in Hz here if not defined in Makefile */
15#ifndef F_CPU
16#define F_CPU 16000000UL
17#endif
18
19/* I2C clock in Hz */
20#define SCL_CLOCK 400000L
21
22
23/*************************************************************************
24 Initialization of the I2C bus interface. Need to be called only once
25*************************************************************************/
26void i2c_init(void)
27{
28 /* initialize TWI clock
29 * minimal values in Bit Rate Register (TWBR) and minimal Prescaler
30 * bits in the TWI Status Register should give us maximal possible
31 * I2C bus speed - about 444 kHz
32 *
33 * for more details, see 20.5.2 in ATmega16/32 secification
34 */
35
36 TWSR = 0; /* no prescaler */
37 TWBR = 10; /* must be >= 10 for stable operation */
38
39}/* i2c_init */
40
41
42/*************************************************************************
43 Issues a start condition and sends address and transfer direction.
44 return 0 = device accessible, 1= failed to access device
45*************************************************************************/
46unsigned char i2c_start(unsigned char address)
47{
48 uint8_t twst;
49
50 /* send START condition */
51 TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
52
53 /* wait until transmission completed */
54 while(!(TWCR & (1<<TWINT)));
55
56 /* check value of TWI Status Register. Mask prescaler bits. */
57 twst = TW_STATUS & 0xF8;
58 if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;
59
60 /* send device address */
61 TWDR = address;
62 TWCR = (1<<TWINT) | (1<<TWEN);
63
64 /* wail until transmission completed and ACK/NACK has been received */
65 while(!(TWCR & (1<<TWINT)));
66
67 /* check value of TWI Status Register. Mask prescaler bits. */
68 twst = TW_STATUS & 0xF8;
69 if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;
70
71 return 0;
72
73}/* i2c_start */
74
75
76/*************************************************************************
77 Issues a start condition and sends address and transfer direction.
78 If device is busy, use ack polling to wait until device is ready
79
80 Input: address and transfer direction of I2C device
81*************************************************************************/
82void i2c_start_wait(unsigned char address)
83{
84 uint8_t twst;
85
86
87 while ( 1 )
88 {
89 /* send START condition */
90 TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
91
92 /* wait until transmission completed */
93 while(!(TWCR & (1<<TWINT)));
94
95 /* check value of TWI Status Register. Mask prescaler bits. */
96 twst = TW_STATUS & 0xF8;
97 if ( (twst != TW_START) && (twst != TW_REP_START)) continue;
98
99 /* send device address */
100 TWDR = address;
101 TWCR = (1<<TWINT) | (1<<TWEN);
102
103 /* wail until transmission completed */
104 while(!(TWCR & (1<<TWINT)));
105
106 /* check value of TWI Status Register. Mask prescaler bits. */
107 twst = TW_STATUS & 0xF8;
108 if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
109 {
110 /* device busy, send stop condition to terminate write operation */
111 TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
112
113 /* wait until stop condition is executed and bus released */
114 while(TWCR & (1<<TWSTO));
115
116 continue;
117 }
118
119 break;
120 }
121
122}/* i2c_start_wait */
123
124
125/*************************************************************************
126 Issues a repeated start condition and sends address and transfer direction
127
128 Input: address and transfer direction of I2C device
129
130 Return: 0 device accessible
131 1 failed to access device
132*************************************************************************/
133unsigned char i2c_rep_start(unsigned char address)
134{
135 return i2c_start( address );
136
137}/* i2c_rep_start */
138
139
140/*************************************************************************
141 Terminates the data transfer and releases the I2C bus
142*************************************************************************/
143void i2c_stop(void)
144{
145 /* send stop condition */
146 TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
147
148 /* wait until stop condition is executed and bus released */
149 while(TWCR & (1<<TWSTO));
150
151}/* i2c_stop */
152
153
154/*************************************************************************
155 Send one byte to I2C device
156
157 Input: byte to be transfered
158 Return: 0 write successful
159 1 write failed
160*************************************************************************/
161unsigned char i2c_write( unsigned char data )
162{
163 uint8_t twst;
164
165 /* send data to the previously addressed device */
166 TWDR = data;
167 TWCR = (1<<TWINT) | (1<<TWEN);
168
169 /* wait until transmission completed */
170 while(!(TWCR & (1<<TWINT)));
171
172 /* check value of TWI Status Register. Mask prescaler bits */
173 twst = TW_STATUS & 0xF8;
174 if( twst != TW_MT_DATA_ACK) return 1;
175 return 0;
176
177}/* i2c_write */
178
179
180/*************************************************************************
181 Read one byte from the I2C device, request more data from device
182
183 Return: byte read from I2C device
184*************************************************************************/
185unsigned char i2c_readAck(void)
186{
187 TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
188 while(!(TWCR & (1<<TWINT)));
189
190 return TWDR;
191
192}/* i2c_readAck */
193
194
195/*************************************************************************
196 Read one byte from the I2C device, read is followed by a stop condition
197
198 Return: byte read from I2C device
199*************************************************************************/
200unsigned char i2c_readNak(void)
201{
202 TWCR = (1<<TWINT) | (1<<TWEN);
203 while(!(TWCR & (1<<TWINT)));
204
205 return TWDR;
206
207}/* i2c_readNak */
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-05 07:21:17 +0000