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1 | 316 | bpoole | /* @file spi.c
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2 | * @brief
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3 | * SPI module
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4 | * @bug broken
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5 | 252 | kwoo | */
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6 | |||
7 | 316 | bpoole | #include <avr/interrupt.h> |
8 | #include "ring_buffer.h" |
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9 | #include "spi.h" |
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10 | #include <dragonfly_lib.h> |
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11 | |||
12 | |||
13 | 252 | kwoo | /*
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14 | SS = PB0
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15 | SCK = PB1
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16 | MOSI = PB2
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17 | MISO = PB3
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18 | */
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19 | 316 | bpoole | /* Controls clock freq. see Table 72 of specs*/
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20 | 252 | kwoo | |
21 | #define DOUBLE_SCK 1 |
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22 | #define SPR0_BIT 1 |
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23 | 316 | bpoole | #define SPR1_BIT 0 |
24 | 252 | kwoo | #define LSB 1 |
25 | #define MSB 0 |
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26 | |||
27 | |||
28 | 350 | kwoo | RING_BUFFER_NEW(spi_buffer, 16, char, spi_send_buff, spi_rec_buff); |
29 | 316 | bpoole | volatile char spi_status; |
30 | 367 | kwoo | char spi_mode;
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31 | 316 | bpoole | static spi_fun_recv_t spi_recv_function;
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32 | 367 | kwoo | //static spi_fun_send_t spi_send_function;
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33 | 252 | kwoo | |
34 | 316 | bpoole | |
35 | 367 | kwoo | void spi_init(char mode, spi_fun_recv_t recv_func) { |
36 | 316 | bpoole | usb_puts("spi_init: start\n");
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37 | 252 | kwoo | |
38 | 367 | kwoo | spi_mode = mode; |
39 | |||
40 | 252 | kwoo | RING_BUFFER_CLEAR(spi_send_buff); |
41 | RING_BUFFER_CLEAR(spi_rec_buff); |
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42 | 316 | bpoole | |
43 | spi_recv_function = recv_func; |
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44 | 367 | kwoo | //spi_send_function = send_func;
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45 | 316 | bpoole | |
46 | 350 | kwoo | /* Enables the SPI module
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47 | * Enable Interrupt, Enable SPI Module, LSB First, Master Mode, Clock div = 64
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48 | */
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49 | SPCR = 0x00;
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50 | 565 | kwoo | if (spi_mode == MASTER) {
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51 | SPCR = _BV(SPIE) | _BV(SPE) | _BV(DORD) | _BV(MSTR)| _BV(SPR1) | _BV(SPR0); |
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52 | } else {
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53 | SPCR = _BV(SPIE) | _BV(SPE) | _BV(DORD) | ~_BV(MSTR)| _BV(SPR1) | _BV(SPR0); |
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54 | } |
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55 | |||
56 | 350 | kwoo | SPSR = 0x00;
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57 | SPSR = _BV(SPI2X); |
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58 | 252 | kwoo | |
59 | 546 | kwoo | spi_status = SPI_IDLE; |
60 | 316 | bpoole | |
61 | 350 | kwoo | /* Set SCLK, SS, MOSI as outputs. MISO as input */
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62 | 565 | kwoo | if(spi_mode == MASTER) {
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63 | 350 | kwoo | DDRB |= MOSI | SCLK | SS; |
64 | DDRB &= ~MISO; |
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65 | 367 | kwoo | PORTB |= SS; //Keep SS High until transmit
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66 | 350 | kwoo | /* Set SCLK, SS, MOSI as inputs. MISO as output */
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67 | } else {
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68 | DDRB &= ~MOSI & ~SCLK & ~SS; |
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69 | DDRB |= MISO; |
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70 | } |
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71 | 252 | kwoo | |
72 | 350 | kwoo | //sei();
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73 | 565 | kwoo | //usb_puts("spi_init: end\n");
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74 | 252 | kwoo | } |
75 | |||
76 | 546 | kwoo | int spi_send(char *data, int bytes) { |
77 | 350 | kwoo | |
78 | int i;
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79 | |||
80 | if(bytes == 0) |
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81 | return -1; /* ...needed?*/ |
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82 | 316 | bpoole | |
83 | 350 | kwoo | //Prevent race condition on the buffer
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84 | 316 | bpoole | cli(); |
85 | for(i = 1; i < bytes; i++) { |
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86 | 350 | kwoo | // Fail if the buffer is full
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87 | if(RING_BUFFER_FULL(spi_send_buff)) {
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88 | sei(); |
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89 | return -1; |
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90 | } |
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91 | |||
92 | RING_BUFFER_ADD(spi_send_buff, data[i]); |
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93 | 252 | kwoo | } |
94 | 350 | kwoo | |
95 | 316 | bpoole | sei(); |
96 | 350 | kwoo | |
97 | 490 | bpoole | spi_status |= SPI_SEND; |
98 | 367 | kwoo | |
99 | if (spi_mode == MASTER ){
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100 | PORTB &= ~SS; //Select slave
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101 | } |
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102 | 495 | kwoo | |
103 | 316 | bpoole | SPDR = *data; |
104 | 565 | kwoo | /*
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105 | 490 | bpoole | if(spi_mode)
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106 | usb_puts("MASTER");
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107 | else
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108 | usb_puts("SLAVE");
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109 | 495 | kwoo | |
110 | 490 | bpoole | usb_puts(": sending [");usb_putc(*data);usb_puts("]\n\r");
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111 | 565 | kwoo | */
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112 | 316 | bpoole | //sei();
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113 | 367 | kwoo | |
114 | return 1; |
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115 | 252 | kwoo | } |
116 | |||
117 | 495 | kwoo | void spi_read(int bytes) { |
118 | |||
119 | cli(); |
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120 | 546 | kwoo | for(int i = 1; i < bytes; i++) { |
121 | 495 | kwoo | // Fail if the buffer is full
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122 | if(RING_BUFFER_FULL(spi_send_buff)) {
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123 | sei(); |
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124 | 546 | kwoo | return;
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125 | 495 | kwoo | } |
126 | |||
127 | 565 | kwoo | RING_BUFFER_ADD(spi_send_buff, '0');
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128 | 495 | kwoo | } |
129 | |||
130 | sei(); |
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131 | |||
132 | spi_status |= SPI_RECV; |
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133 | |||
134 | if (spi_mode == MASTER ){
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135 | PORTB &= ~SS; //Select slave
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136 | } |
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137 | |||
138 | 565 | kwoo | SPDR = '0';
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139 | 495 | kwoo | |
140 | } |
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141 | |||
142 | 490 | bpoole | void spi_read_one(void) |
143 | { |
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144 | 367 | kwoo | PORTB &= ~SS; |
145 | 490 | bpoole | SPDR = 'x';
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146 | 367 | kwoo | } |
147 | |||
148 | 316 | bpoole | ISR(SIG_SPI) { |
149 | 367 | kwoo | char c;
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150 | 546 | kwoo | |
151 | 564 | kwoo | //You always receive something. You need to handle it before you overwrite it.
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152 | spi_recv_function(SPDR); |
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153 | |||
154 | 546 | kwoo | //The clock is running so dequeue another byte to send
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155 | 490 | bpoole | if(!RING_BUFFER_EMPTY(spi_send_buff)) {//cheap way to test if SPI_SEND |
156 | RING_BUFFER_REMOVE(spi_send_buff, c); |
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157 | SPDR = c; |
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158 | 546 | kwoo | //If we're the master and we're done sending, end the transmission
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159 | } else if (spi_mode == MASTER) { |
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160 | 495 | kwoo | PORTB |= SS; |
161 | 565 | kwoo | } else if (spi_mode == SLAVE) { |
162 | SPDR = '0';
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163 | 495 | kwoo | } |
164 | |||
165 | 564 | kwoo | |
166 | 546 | kwoo | |
167 | /*
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168 | if(spi_status & SPI_SEND) {
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169 | spi_status ^= SPI_SEND;
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170 | |||
171 | if (spi_mode == MASTER) {
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172 | PORTB |= SS;
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173 | }
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174 | } else if (spi_status & SPI_RECV) {
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175 | |||
176 | }
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177 | */
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178 | //End the transmission if we are not sending or recieving anymore
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179 | //} else if(spi_mode == MASTER) {
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180 | // PORTB |= SS;
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181 | //}
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182 | |||
183 | 495 | kwoo | //Call the recv function whenver we recieve a byte
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184 | 546 | kwoo | //if(spi_status == SPI_RECV){
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185 | //spi_recv_function(SPDR);
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186 | 495 | kwoo | //if(spi_mode == MASTER)
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187 | //PORTB |= SS;
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188 | 546 | kwoo | //}
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189 | 490 | bpoole | } |