Subversion Repositories FlightCtrl

Rev

Details | Last modification | View Log | RSS feed

Rev Author Line No. Line
1 ingob 1
/*############################################################################
2
############################################################################*/
3
 
687 killagreg 4
#include <avr/io.h>
5
#include <avr/interrupt.h>
6
 
1 ingob 7
#include "main.h"
685 killagreg 8
#include "twimaster.h"
9
#include "fc.h"
1 ingob 10
 
694 killagreg 11
volatile uint8_t twi_state = 0;
12
volatile uint8_t motor = 0;
13
volatile uint8_t motor_rx[8];
1 ingob 14
 
694 killagreg 15
/**************************************************/
16
/*   Initialize I2C (TWI)                         */
17
/**************************************************/
726 killagreg 18
void I2C_Init(void)
1 ingob 19
{
694 killagreg 20
        uint8_t sreg = SREG;
21
        cli();
22
 
23
        // SDA is INPUT
24
        DDRC  &= ~(1<<DDC1);
25
        // SCL is output
26
        DDRC |= (1<<DDC0);
27
        // pull up SDA
28
        PORTC |= (1<<PORTC0)|(1<<PORTC1);
29
 
30
        // TWI Status Register
31
        // prescaler 1 (TWPS1 = 0, TWPS0 = 0)
32
        TWSR &= ~((1<<TWPS1)|(1<<TWPS0));
33
 
34
        // set TWI Bit Rate Register
35
        TWBR = ((SYSCLK/SCL_CLOCK)-16)/2;
36
 
37
        SREG = sreg;
1 ingob 38
}
39
 
694 killagreg 40
/****************************************/
41
/*   Start I2C                          */
42
/****************************************/
726 killagreg 43
void I2C_Start(void)
1 ingob 44
{
694 killagreg 45
        // TWI Control Register
46
        // clear TWI interrupt flag (TWINT=1)
47
        // disable TWI Acknowledge Bit (TWEA = 0)
48
        // enable TWI START Condition Bit (TWSTA = 1), MASTER
49
        // disable TWI STOP Condition Bit (TWSTO = 0)
50
        // disable TWI Write Collision Flag (TWWC = 0)
51
        // enable i2c (TWIE = 1)
52
        // enable TWI Interrupt (TWIE = 1)
53
    TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN) | (1<<TWIE);
1 ingob 54
}
55
 
694 killagreg 56
/****************************************/
57
/*    Stop I2C                          */
58
/****************************************/
726 killagreg 59
void I2C_Stop(void)
1 ingob 60
{
694 killagreg 61
        // TWI Control Register
62
        // clear TWI interrupt flag (TWINT=1)
63
        // disable TWI Acknowledge Bit (TWEA = 0)
64
        // diable TWI START Condition Bit (TWSTA = 1), no MASTER
65
        // enable TWI STOP Condition Bit (TWSTO = 1)
66
        // disable TWI Write Collision Flag (TWWC = 0)
67
        // enable i2c (TWIE = 1)
68
        // disable TWI Interrupt (TWIE = 0)
69
    TWCR = (1<<TWINT) | (1<<TWSTO) | (1<<TWEN);
1 ingob 70
}
71
 
694 killagreg 72
/****************************************/
73
/*    Reset I2C                         */
74
/****************************************/
726 killagreg 75
void I2C_Reset(void)
173 holgerb 76
{
694 killagreg 77
        // stop i2c bus
726 killagreg 78
        I2C_Stop();
694 killagreg 79
        twi_state = 0;
80
        motor = TWDR; // ??
81
        motor = 0;
82
        TWCR = (1<<TWINT); // reset to original state incl. interrupt flag reset
83
        TWAMR = 0;
84
        TWAR = 0;
85
        TWDR = 0;
86
        TWSR = 0;
87
        TWBR = 0;
726 killagreg 88
        I2C_Init();
89
        I2C_Start();
90
        I2C_WriteByte(0);
173 holgerb 91
}
92
 
694 killagreg 93
/****************************************/
94
/*    Write to I2C                      */
95
/****************************************/
726 killagreg 96
void I2C_WriteByte(int8_t byte)
685 killagreg 97
{
694 killagreg 98
    // move byte to send into TWI Data Register
1 ingob 99
    TWDR = byte;
694 killagreg 100
    // clear interrupt flag (TWINT = 1)
101
    // enable i2c bus (TWEN = 1)
102
    // enable intterupt (TWIW = 1)
1 ingob 103
    TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE);
694 killagreg 104
}
685 killagreg 105
 
106
 
694 killagreg 107
/****************************************/
108
/*    Receive byte and send ACK         */
109
/****************************************/
726 killagreg 110
void I2C_ReceiveByte(void)
694 killagreg 111
{
112
   TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE) | (1<<TWEA);
1 ingob 113
}
114
 
694 killagreg 115
/****************************************/
116
/* I2C receive last byte and send no ACK*/
117
/****************************************/
726 killagreg 118
void I2C_ReceiveLastByte(void)
1 ingob 119
{
694 killagreg 120
   TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE);
121
}
122
 
123
 
124
/****************************************/
125
/*        I2C ISR                       */
126
/****************************************/
127
ISR (TWI_vect)
128
 
129
{
130
        static uint8_t motorread = 0;
131
 
132
    switch (twi_state++) // First i2s_start from SendMotorData()
1 ingob 133
        {
694 killagreg 134
                // Master Transmit
135
        case 0: // Send SLA-W
726 killagreg 136
                I2C_WriteByte(0x52+(motor*2));
1 ingob 137
                break;
694 killagreg 138
        case 1: // Send Data to Salve
1 ingob 139
                switch(motor++)
140
                    {
141
                    case 0:
726 killagreg 142
                            I2C_WriteByte(Motor_Front);
1 ingob 143
                            break;
685 killagreg 144
                    case 1:
726 killagreg 145
                            I2C_WriteByte(Motor_Rear);
1 ingob 146
                            break;
147
                    case 2:
726 killagreg 148
                            I2C_WriteByte(Motor_Right);
1 ingob 149
                            break;
150
                    case 3:
726 killagreg 151
                            I2C_WriteByte(Motor_Left);
1 ingob 152
                            break;
153
                    }
154
                break;
694 killagreg 155
        case 2: // repeat case 0+1 for all Slaves
1 ingob 156
                if (motor<4) twi_state = 0;
726 killagreg 157
                I2C_Start(); // Repeated start -> switch salve or switch Master Transmit -> Master Receive
685 killagreg 158
                break;
159
 
694 killagreg 160
        // Master Receive
161
        case 3: // Send SLA-R
726 killagreg 162
                I2C_WriteByte(0x53+(motorread*2));
1 ingob 163
                break;
164
        case 4:
694 killagreg 165
                //Transmit 1st byte
726 killagreg 166
                                I2C_ReceiveByte();
1 ingob 167
                break;
694 killagreg 168
        case 5: //Read 1st byte and transmit 2nd Byte
1 ingob 169
                motor_rx[motorread] = TWDR;
726 killagreg 170
                                I2C_ReceiveLastByte();
694 killagreg 171
                                break;
172
        case 6:
173
                //Read 2nd byte
174
                                motor_rx[motorread+4] = TWDR;
175
                                motorread++;
176
                if (motorread > 3) motorread=0;
173 holgerb 177
 
694 killagreg 178
        default:
726 killagreg 179
                I2C_Stop();
694 killagreg 180
                twi_state = 0;
173 holgerb 181
                I2CTimeout = 10;
694 killagreg 182
                motor = 0;
1 ingob 183
        }
184
}