| 202 |
Kevin |
1 |
#include <xc.h>
|
|
|
2 |
#include "main.h"
|
|
|
3 |
#include "I2C.h"
|
|
|
4 |
|
|
|
5 |
static I2C_DATA *data_ptr;
|
|
|
6 |
|
|
|
7 |
// Set up the data structures for the base_I2C.code
|
|
|
8 |
// Should be called once before any i2c routines are called
|
|
|
9 |
void I2C_Init(I2C_DATA *data) {
|
|
|
10 |
data_ptr = data;
|
|
|
11 |
|
|
|
12 |
I2C_CLK_TRIS = 1;
|
|
|
13 |
I2C_DAT_TRIS = 1;
|
|
|
14 |
|
|
|
15 |
data_ptr->buffer_in_len = 0;
|
|
|
16 |
data_ptr->buffer_in_len_tmp = 0;
|
|
|
17 |
data_ptr->buffer_in_read_ind = 0;
|
|
|
18 |
data_ptr->buffer_in_write_ind = 0;
|
|
|
19 |
|
|
|
20 |
data_ptr->buffer_out_ind = 0;
|
|
|
21 |
data_ptr->buffer_out_len = 0;
|
|
|
22 |
|
|
|
23 |
data_ptr->operating_mode = 0;
|
|
|
24 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
25 |
data_ptr->return_status = 0;
|
|
|
26 |
|
|
|
27 |
data_ptr->slave_in_last_byte = 0;
|
|
|
28 |
data_ptr->slave_sending_data = 0;
|
|
|
29 |
|
|
|
30 |
data_ptr->master_dest_addr = 0;
|
|
|
31 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
32 |
|
|
|
33 |
// Enable I2C interrupt
|
|
|
34 |
PIE1bits.SSP1IE = 1;
|
|
|
35 |
}
|
|
|
36 |
|
|
|
37 |
// Setup the PIC to operate as a master.
|
|
|
38 |
void I2C_Configure_Master(char speed) {
|
|
|
39 |
data_ptr->operating_mode = I2C_MODE_MASTER;
|
|
|
40 |
|
|
|
41 |
SSP1STAT = 0x0;
|
|
|
42 |
SSP1CON1 = 0x0;
|
|
|
43 |
SSP1CON2 = 0x0;
|
|
|
44 |
SSP1CON3 = 0x0;
|
|
|
45 |
SSP1CON1bits.SSPM = 0x8; // I2C Master Mode
|
|
|
46 |
if (speed) {
|
|
|
47 |
SSP1ADD = 0x4F; // Operate at 100KHz (32MHz)
|
|
|
48 |
} else {
|
|
|
49 |
SSP1ADD = 0x13; // Operate at 400KHz (32MHz)
|
|
|
50 |
}
|
|
|
51 |
SSP1STATbits.SMP = 1; // Disable Slew Rate Control
|
|
|
52 |
SSP1CON3bits.PCIE = 1; // Stop condition interrupt enable
|
|
|
53 |
SSP1CON3bits.SCIE = 1; // Start condition interrupt enable
|
|
|
54 |
SSP1CON1bits.SSPEN = 1; // Enable MSSP Module
|
|
|
55 |
}
|
|
|
56 |
|
|
|
57 |
// Sends length number of bytes in msg to specified address (no R/W bit)
|
| 223 |
Kevin |
58 |
void I2C_Master_Send(char address, char *msg, char length) {
|
| 202 |
Kevin |
59 |
char i;
|
|
|
60 |
if (length == 0)
|
|
|
61 |
return;
|
|
|
62 |
|
|
|
63 |
// Copy message to send into buffer and save length/address
|
|
|
64 |
for (i = 0; i < length; i++) {
|
|
|
65 |
data_ptr->buffer_in[i] = msg[i];
|
|
|
66 |
}
|
|
|
67 |
data_ptr->buffer_in_len = length;
|
|
|
68 |
data_ptr->master_dest_addr = address;
|
|
|
69 |
data_ptr->buffer_in_read_ind = 0;
|
|
|
70 |
data_ptr->buffer_in_write_ind = 0;
|
|
|
71 |
|
|
|
72 |
// Change status to 'next' operation
|
|
|
73 |
data_ptr->operating_state = I2C_SEND_ADDR;
|
|
|
74 |
data_ptr->master_status = I2C_MASTER_SEND;
|
|
|
75 |
|
|
|
76 |
// Generate start condition
|
|
|
77 |
SSP1CON2bits.SEN = 1;
|
|
|
78 |
}
|
|
|
79 |
|
|
|
80 |
// Reads length number of bytes from address (no R/W bit)
|
|
|
81 |
void I2C_Master_Recv(char address, char length) {
|
|
|
82 |
if (length == 0)
|
|
|
83 |
return;
|
|
|
84 |
|
|
|
85 |
// Save length and address to get data from
|
|
|
86 |
data_ptr->buffer_in_len = length;
|
|
|
87 |
data_ptr->master_dest_addr = address;
|
|
|
88 |
data_ptr->buffer_in_read_ind = 0;
|
|
|
89 |
data_ptr->buffer_in_write_ind = 0;
|
|
|
90 |
|
|
|
91 |
// Change status to 'next' operation
|
|
|
92 |
data_ptr->operating_state = I2C_SEND_ADDR;
|
|
|
93 |
data_ptr->master_status = I2C_MASTER_RECV;
|
|
|
94 |
|
|
|
95 |
// Generate start condition
|
|
|
96 |
SSP1CON2bits.SEN = 1;
|
|
|
97 |
}
|
|
|
98 |
|
|
|
99 |
// Writes msg to address then reads length number of bytes from address
|
|
|
100 |
void I2C_Master_Restart(char address, char msg, char length) {
|
|
|
101 |
char c;
|
|
|
102 |
if (length == 0) {
|
|
|
103 |
c = msg;
|
| 223 |
Kevin |
104 |
I2C_Master_Send(address, &c, 1);
|
| 202 |
Kevin |
105 |
return;
|
|
|
106 |
}
|
|
|
107 |
|
|
|
108 |
// Save length and address to get data from
|
|
|
109 |
data_ptr->buffer_in[0] = msg;
|
|
|
110 |
data_ptr->buffer_in_len = length;
|
|
|
111 |
data_ptr->master_dest_addr = address;
|
|
|
112 |
data_ptr->buffer_in_read_ind = 0;
|
|
|
113 |
data_ptr->buffer_in_write_ind = 0;
|
|
|
114 |
|
|
|
115 |
// Change status to 'next' operation
|
|
|
116 |
data_ptr->operating_state = I2C_SEND_ADDR;
|
|
|
117 |
data_ptr->master_status = I2C_MASTER_RESTART;
|
|
|
118 |
|
|
|
119 |
// Generate start condition
|
|
|
120 |
SSP1CON2bits.SEN = 1;
|
|
|
121 |
}
|
|
|
122 |
|
|
|
123 |
// Setup the PIC to operate as a slave. The address must not include the R/W bit
|
|
|
124 |
void I2C_Configure_Slave(char addr) {
|
|
|
125 |
data_ptr->operating_mode = I2C_MODE_SLAVE;
|
|
|
126 |
|
|
|
127 |
SSP1ADD = addr << 1; // Set the slave address
|
|
|
128 |
|
|
|
129 |
SSP1STAT = 0x0;
|
|
|
130 |
SSP1CON1 = 0x0;
|
|
|
131 |
SSP1CON2 = 0x0;
|
|
|
132 |
SSP1CON3 = 0x0;
|
|
|
133 |
SSP1CON1bits.SSPM = 0xE; // Enable Slave 7-bit w/ start/stop interrupts
|
|
|
134 |
SSP1STATbits.SMP = 1; // Slew Off
|
|
|
135 |
SSP1CON2bits.SEN = 1; // Enable clock-stretching
|
|
|
136 |
SSP1CON1bits.SSPEN = 1; // Enable MSSP Module
|
|
|
137 |
}
|
|
|
138 |
|
|
|
139 |
void I2C_Interrupt_Handler() {
|
|
|
140 |
// Call interrupt depending on which mode we are operating in
|
|
|
141 |
if (data_ptr->operating_mode == I2C_MODE_MASTER) {
|
|
|
142 |
I2C_Interrupt_Master();
|
|
|
143 |
} else if (data_ptr->operating_mode == I2C_MODE_SLAVE) {
|
|
|
144 |
I2C_Interrupt_Slave();
|
|
|
145 |
}
|
|
|
146 |
}
|
|
|
147 |
|
|
|
148 |
// An internal subroutine used in the master version of the i2c_interrupt_handler
|
|
|
149 |
void I2C_Interrupt_Master() {
|
|
|
150 |
// If we are in the middle of sending data
|
|
|
151 |
if (data_ptr->master_status == I2C_MASTER_SEND) {
|
|
|
152 |
switch (data_ptr->operating_state) {
|
|
|
153 |
case I2C_IDLE:
|
|
|
154 |
break;
|
|
|
155 |
case I2C_SEND_ADDR:
|
|
|
156 |
// Send the address with read bit set
|
|
|
157 |
data_ptr->operating_state = I2C_CHECK_ACK_SEND;
|
|
|
158 |
SSP1BUF = (data_ptr->master_dest_addr << 1) | 0x0;
|
|
|
159 |
break;
|
|
|
160 |
case I2C_CHECK_ACK_SEND:
|
|
|
161 |
// Check if ACK is received or not
|
|
|
162 |
if (!SSP1CON2bits.ACKSTAT) {
|
|
|
163 |
// If an ACK is received, send next byte of data
|
|
|
164 |
if (data_ptr->buffer_in_read_ind < data_ptr->buffer_in_len) {
|
|
|
165 |
SSP1BUF = data_ptr->buffer_in[data_ptr->buffer_in_read_ind];
|
|
|
166 |
data_ptr->buffer_in_read_ind++;
|
|
|
167 |
} else {
|
|
|
168 |
// If no more data is to be sent, send stop bit
|
|
|
169 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
170 |
SSP1CON2bits.PEN = 1;
|
|
|
171 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
172 |
data_ptr->return_status = I2C_SEND_OK;
|
|
|
173 |
}
|
|
|
174 |
} else {
|
|
|
175 |
// If a NACK is received, stop transmission and send error
|
|
|
176 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
177 |
SSP1CON2bits.PEN = 1;
|
|
|
178 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
179 |
data_ptr->return_status = I2C_SEND_FAIL;
|
|
|
180 |
}
|
|
|
181 |
break;
|
|
|
182 |
}
|
|
|
183 |
// If we are in the middle of receiving data
|
|
|
184 |
} else if (data_ptr->master_status == I2C_MASTER_RECV) {
|
|
|
185 |
switch (data_ptr->operating_state) {
|
|
|
186 |
case I2C_IDLE:
|
|
|
187 |
break;
|
|
|
188 |
case I2C_SEND_ADDR:
|
|
|
189 |
// Send address with write bit set
|
|
|
190 |
data_ptr->operating_state = I2C_CHECK_ACK_RECV;
|
| 222 |
Kevin |
191 |
char tmp = (data_ptr->master_dest_addr << 1);
|
|
|
192 |
tmp |= 0x1;
|
|
|
193 |
SSP1BUF = tmp;
|
| 202 |
Kevin |
194 |
break;
|
|
|
195 |
case I2C_CHECK_ACK_RECV:
|
|
|
196 |
// Check if ACK is received
|
|
|
197 |
if (!SSP1CON2bits.ACKSTAT) {
|
|
|
198 |
// If an ACK is received, set module to receive 1 byte of data
|
|
|
199 |
data_ptr->operating_state = I2C_RCV_DATA;
|
|
|
200 |
SSP1CON2bits.RCEN = 1;
|
|
|
201 |
} else {
|
|
|
202 |
// If a NACK is received, stop transmission and send error
|
|
|
203 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
204 |
SSP1CON2bits.PEN = 1;
|
|
|
205 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
206 |
data_ptr->return_status = I2C_RECV_FAIL;
|
|
|
207 |
}
|
|
|
208 |
break;
|
|
|
209 |
case I2C_RCV_DATA:
|
|
|
210 |
// On receive, save byte into buffer
|
|
|
211 |
// TODO: Handle I2C buffer overflow
|
|
|
212 |
data_ptr->buffer_in[data_ptr->buffer_in_write_ind] = SSP1BUF;
|
|
|
213 |
data_ptr->buffer_in_write_ind++;
|
|
|
214 |
if (data_ptr->buffer_in_write_ind < data_ptr->buffer_in_len) {
|
|
|
215 |
// If we still need to read, send an ACK to the slave
|
|
|
216 |
data_ptr->operating_state = I2C_REQ_DATA;
|
|
|
217 |
SSP1CON2bits.ACKDT = 0; // ACK
|
|
|
218 |
SSP1CON2bits.ACKEN = 1;
|
|
|
219 |
} else {
|
|
|
220 |
// If we are done reading, send an NACK to the slave
|
|
|
221 |
data_ptr->operating_state = I2C_SEND_STOP;
|
|
|
222 |
SSP1CON2bits.ACKDT = 1; // NACK
|
|
|
223 |
SSP1CON2bits.ACKEN = 1;
|
|
|
224 |
}
|
|
|
225 |
break;
|
|
|
226 |
case I2C_REQ_DATA:
|
|
|
227 |
// Set module to receive one byte of data
|
|
|
228 |
data_ptr->operating_state = I2C_RCV_DATA;
|
|
|
229 |
SSP1CON2bits.RCEN = 1;
|
|
|
230 |
break;
|
|
|
231 |
case I2C_SEND_STOP:
|
|
|
232 |
// Send the stop bit and copy message to send to Main()
|
|
|
233 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
234 |
SSP1CON2bits.PEN = 1;
|
|
|
235 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
236 |
data_ptr->return_status = I2C_RECV_OK;
|
|
|
237 |
break;
|
|
|
238 |
}
|
|
|
239 |
} else if (data_ptr->master_status == I2C_MASTER_RESTART) {
|
|
|
240 |
switch (data_ptr->operating_state) {
|
|
|
241 |
case I2C_IDLE:
|
|
|
242 |
break;
|
|
|
243 |
case I2C_SEND_ADDR:
|
| 222 |
Kevin |
244 |
// Send the address with write bit set
|
| 202 |
Kevin |
245 |
data_ptr->operating_state = I2C_CHECK_ACK_SEND;
|
|
|
246 |
SSP1BUF = (data_ptr->master_dest_addr << 1) | 0x0;
|
|
|
247 |
break;
|
|
|
248 |
case I2C_CHECK_ACK_SEND:
|
|
|
249 |
// Check if ACK is received or not
|
|
|
250 |
if (!SSP1CON2bits.ACKSTAT) {
|
|
|
251 |
// If an ACK is received, send first byte of data
|
|
|
252 |
SSP1BUF = data_ptr->buffer_in[0];
|
|
|
253 |
data_ptr->operating_state = I2C_CHECK_ACK_RESTART;
|
|
|
254 |
} else {
|
|
|
255 |
// If a NACK is received, stop transmission and send error
|
|
|
256 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
257 |
SSP1CON2bits.PEN = 1;
|
|
|
258 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
259 |
data_ptr->return_status = I2C_SEND_FAIL;
|
|
|
260 |
}
|
|
|
261 |
break;
|
|
|
262 |
case I2C_CHECK_ACK_RESTART:
|
|
|
263 |
if (!SSP1CON2bits.ACKSTAT) {
|
|
|
264 |
SSP1CON2bits.RSEN = 1;
|
|
|
265 |
data_ptr->operating_state = I2C_SEND_ADDR_2;
|
|
|
266 |
} else {
|
|
|
267 |
// If a NACK is received, stop transmission and send error
|
|
|
268 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
269 |
SSP1CON2bits.PEN = 1;
|
|
|
270 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
271 |
data_ptr->return_status = I2C_SEND_FAIL;
|
|
|
272 |
}
|
|
|
273 |
break;
|
|
|
274 |
case I2C_SEND_ADDR_2:
|
|
|
275 |
// Send the address with read bit set
|
|
|
276 |
data_ptr->operating_state = I2C_CHECK_ACK_RECV;
|
| 222 |
Kevin |
277 |
char tmp = (data_ptr->master_dest_addr << 1);
|
|
|
278 |
tmp |= 0x1;
|
|
|
279 |
SSP1BUF = tmp;
|
| 202 |
Kevin |
280 |
break;
|
|
|
281 |
case I2C_CHECK_ACK_RECV:
|
|
|
282 |
// Check if ACK is received
|
|
|
283 |
if (!SSP1CON2bits.ACKSTAT) {
|
|
|
284 |
// If an ACK is received, set module to receive 1 byte of data
|
|
|
285 |
data_ptr->operating_state = I2C_RCV_DATA;
|
|
|
286 |
SSP1CON2bits.RCEN = 1;
|
|
|
287 |
} else {
|
|
|
288 |
// If a NACK is received, stop transmission and send error
|
|
|
289 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
290 |
SSP1CON2bits.PEN = 1;
|
|
|
291 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
292 |
data_ptr->return_status = I2C_RECV_FAIL;
|
|
|
293 |
}
|
|
|
294 |
break;
|
|
|
295 |
case I2C_RCV_DATA:
|
|
|
296 |
// On receive, save byte into buffer
|
|
|
297 |
// TODO: Handle I2C buffer overflow
|
|
|
298 |
data_ptr->buffer_in[data_ptr->buffer_in_write_ind] = SSP1BUF;
|
|
|
299 |
data_ptr->buffer_in_write_ind++;
|
|
|
300 |
if (data_ptr->buffer_in_write_ind < data_ptr->buffer_in_len) {
|
|
|
301 |
// If we still need to read, send an ACK to the slave
|
|
|
302 |
data_ptr->operating_state = I2C_REQ_DATA;
|
|
|
303 |
SSP1CON2bits.ACKDT = 0; // ACK
|
|
|
304 |
SSP1CON2bits.ACKEN = 1;
|
|
|
305 |
} else {
|
|
|
306 |
// If we are done reading, send an NACK to the slave
|
|
|
307 |
data_ptr->operating_state = I2C_SEND_STOP;
|
|
|
308 |
SSP1CON2bits.ACKDT = 1; // NACK
|
|
|
309 |
SSP1CON2bits.ACKEN = 1;
|
|
|
310 |
}
|
|
|
311 |
break;
|
|
|
312 |
case I2C_REQ_DATA:
|
|
|
313 |
// Set module to receive one byte of data
|
|
|
314 |
data_ptr->operating_state = I2C_RCV_DATA;
|
|
|
315 |
SSP1CON2bits.RCEN = 1;
|
|
|
316 |
break;
|
|
|
317 |
case I2C_SEND_STOP:
|
|
|
318 |
// Send the stop bit and copy message to send to Main()
|
|
|
319 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
320 |
SSP1CON2bits.PEN = 1;
|
|
|
321 |
data_ptr->master_status = I2C_MASTER_IDLE;
|
|
|
322 |
data_ptr->return_status = I2C_RECV_OK;
|
|
|
323 |
break;
|
|
|
324 |
}
|
|
|
325 |
}
|
|
|
326 |
}
|
|
|
327 |
|
|
|
328 |
void I2C_Interrupt_Slave() {
|
|
|
329 |
char received_data;
|
|
|
330 |
char data_read_from_buffer = 0;
|
|
|
331 |
char data_written_to_buffer = 0;
|
|
|
332 |
char overrun_error = 0;
|
|
|
333 |
|
|
|
334 |
// Clear SSPOV (overflow bit)
|
|
|
335 |
if (SSP1CON1bits.SSPOV == 1) {
|
|
|
336 |
SSP1CON1bits.SSPOV = 0;
|
|
|
337 |
// We failed to read the buffer in time, so we know we
|
|
|
338 |
// can't properly receive this message, just put us in the
|
|
|
339 |
// a state where we are looking for a new message
|
|
|
340 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
341 |
overrun_error = 1;
|
|
|
342 |
data_ptr->return_status = I2C_ERR_OVERRUN;
|
|
|
343 |
}
|
|
|
344 |
|
|
|
345 |
// Read SPPxBUF if it is full
|
|
|
346 |
if (SSP1STATbits.BF == 1) {
|
|
|
347 |
received_data = SSP1BUF;
|
|
|
348 |
data_read_from_buffer = 1;
|
|
|
349 |
}
|
|
|
350 |
|
|
|
351 |
if (!overrun_error) {
|
|
|
352 |
switch (data_ptr->operating_state) {
|
|
|
353 |
case I2C_IDLE:
|
|
|
354 |
{
|
|
|
355 |
// Ignore anything except a start
|
|
|
356 |
if (SSP1STATbits.S == 1) {
|
|
|
357 |
data_ptr->buffer_in_len_tmp = 0;
|
|
|
358 |
data_ptr->operating_state = I2C_STARTED;
|
|
|
359 |
// if (data_read_from_buffer) {
|
|
|
360 |
// if (SSPSTATbits.D_A == 1) {
|
|
|
361 |
// DBG_PRINT_I2C("I2C Start: (ERROR) no address recieved\r\n");
|
|
|
362 |
// // This is bad because we got data and we wanted an address
|
|
|
363 |
// data_ptr->operating_state = I2C_IDLE;
|
|
|
364 |
// data_ptr->return_status = I2C_ERR_NOADDR;
|
|
|
365 |
// } else {
|
|
|
366 |
// // Determine if we are sending or receiving data
|
|
|
367 |
// if (SSPSTATbits.R_W == 1) {
|
|
|
368 |
// data_ptr->operating_state = I2C_SEND_DATA;
|
|
|
369 |
// } else {
|
|
|
370 |
// data_ptr->operating_state = I2C_RCV_DATA;
|
|
|
371 |
// }
|
|
|
372 |
// }
|
|
|
373 |
// } else {
|
|
|
374 |
// data_ptr->operating_state = I2C_STARTED;
|
|
|
375 |
// }
|
|
|
376 |
}
|
|
|
377 |
break;
|
|
|
378 |
}
|
|
|
379 |
case I2C_STARTED:
|
|
|
380 |
{
|
|
|
381 |
// In this case, we expect either an address or a stop bit
|
|
|
382 |
if (SSP1STATbits.P == 1) {
|
|
|
383 |
// Return to idle mode
|
|
|
384 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
385 |
} else if (data_read_from_buffer) {
|
|
|
386 |
if (SSP1STATbits.D_nA == 0) {
|
|
|
387 |
// Address received
|
|
|
388 |
if (SSP1STATbits.R_nW == 0) {
|
|
|
389 |
// Slave write mode
|
|
|
390 |
data_ptr->operating_state = I2C_RCV_DATA;
|
|
|
391 |
} else {
|
|
|
392 |
// Slave read mode
|
|
|
393 |
data_ptr->operating_state = I2C_SEND_DATA;
|
|
|
394 |
// Process the first byte immediatly if sending data
|
|
|
395 |
goto send;
|
|
|
396 |
}
|
|
|
397 |
} else {
|
|
|
398 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
399 |
data_ptr->return_status = I2C_ERR_NODATA;
|
|
|
400 |
}
|
|
|
401 |
}
|
|
|
402 |
break;
|
|
|
403 |
}
|
|
|
404 |
send:
|
|
|
405 |
case I2C_SEND_DATA:
|
|
|
406 |
{
|
|
|
407 |
if (!data_ptr->slave_sending_data) {
|
|
|
408 |
// If we are not currently sending data, figure out what to reply with
|
|
|
409 |
if (I2C_Process_Send(data_ptr->slave_in_last_byte)) {
|
|
|
410 |
// Data exists to be returned, send first byte
|
|
|
411 |
SSP1BUF = data_ptr->buffer_out[0];
|
|
|
412 |
data_ptr->buffer_out_ind = 1;
|
|
|
413 |
data_ptr->slave_sending_data = 1;
|
|
|
414 |
data_written_to_buffer = 1;
|
|
|
415 |
} else {
|
|
|
416 |
// Unknown request
|
|
|
417 |
data_ptr->slave_sending_data = 0;
|
|
|
418 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
419 |
}
|
|
|
420 |
} else {
|
|
|
421 |
// Sending remaining data back to master
|
|
|
422 |
if (data_ptr->buffer_out_ind < data_ptr->buffer_out_len) {
|
|
|
423 |
SSP1BUF = data_ptr->buffer_out[data_ptr->buffer_out_ind];
|
|
|
424 |
data_ptr->buffer_out_ind++;
|
|
|
425 |
data_written_to_buffer = 1;
|
|
|
426 |
} else {
|
|
|
427 |
// Nothing left to send
|
|
|
428 |
data_ptr->slave_sending_data = 0;
|
|
|
429 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
430 |
}
|
|
|
431 |
}
|
|
|
432 |
break;
|
|
|
433 |
}
|
|
|
434 |
case I2C_RCV_DATA:
|
|
|
435 |
{
|
|
|
436 |
// We expect either data or a stop bit or a (if a restart, an addr)
|
|
|
437 |
if (SSP1STATbits.P == 1) {
|
|
|
438 |
// Stop bit detected, we need to check to see if we also read data
|
|
|
439 |
if (data_read_from_buffer) {
|
|
|
440 |
if (SSP1STATbits.D_nA == 1) {
|
|
|
441 |
// Data received with stop bit
|
|
|
442 |
// TODO: Handle I2C buffer overflow
|
|
|
443 |
data_ptr->buffer_in[data_ptr->buffer_in_write_ind] = received_data;
|
|
|
444 |
if (data_ptr->buffer_in_write_ind == I2C_BUFFER_SIZE-1) {
|
|
|
445 |
data_ptr->buffer_in_write_ind = 0;
|
|
|
446 |
} else {
|
|
|
447 |
data_ptr->buffer_in_write_ind++;
|
|
|
448 |
}
|
|
|
449 |
data_ptr->buffer_in_len_tmp++;
|
|
|
450 |
// Save the last byte received
|
|
|
451 |
data_ptr->slave_in_last_byte = received_data;
|
|
|
452 |
data_ptr->return_status = I2C_DATA_AVAL;
|
|
|
453 |
} else {
|
|
|
454 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
455 |
data_ptr->return_status = I2C_ERR_NODATA;
|
|
|
456 |
}
|
|
|
457 |
}
|
|
|
458 |
data_ptr->buffer_in_len += data_ptr->buffer_in_len_tmp;
|
|
|
459 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
460 |
} else if (data_read_from_buffer) {
|
|
|
461 |
if (SSP1STATbits.D_nA == 1) {
|
|
|
462 |
// Data received
|
|
|
463 |
data_ptr->buffer_in[data_ptr->buffer_in_write_ind] = received_data;
|
|
|
464 |
if (data_ptr->buffer_in_write_ind == I2C_BUFFER_SIZE-1) {
|
|
|
465 |
data_ptr->buffer_in_write_ind = 0;
|
|
|
466 |
} else {
|
|
|
467 |
data_ptr->buffer_in_write_ind++;
|
|
|
468 |
}
|
|
|
469 |
data_ptr->buffer_in_len_tmp++;
|
|
|
470 |
// Save the last byte received
|
|
|
471 |
data_ptr->slave_in_last_byte = received_data;
|
|
|
472 |
data_ptr->return_status = I2C_DATA_AVAL;
|
|
|
473 |
} else {
|
|
|
474 |
// Restart bit detected
|
|
|
475 |
if (SSP1STATbits.R_nW == 1) {
|
|
|
476 |
data_ptr->buffer_in_len += data_ptr->buffer_in_len_tmp;
|
|
|
477 |
data_ptr->operating_state = I2C_SEND_DATA;
|
|
|
478 |
// Process the first byte immediatly if sending data
|
|
|
479 |
goto send;
|
|
|
480 |
} else {
|
|
|
481 |
// Bad to recv an address again, we aren't ready
|
|
|
482 |
data_ptr->operating_state = I2C_IDLE;
|
|
|
483 |
data_ptr->return_status = I2C_ERR_NODATA;
|
|
|
484 |
}
|
|
|
485 |
}
|
|
|
486 |
}
|
|
|
487 |
break;
|
|
|
488 |
}
|
|
|
489 |
}
|
|
|
490 |
}
|
|
|
491 |
|
|
|
492 |
// Release the clock stretching bit (if we should)
|
|
|
493 |
if (data_read_from_buffer || data_written_to_buffer) {
|
|
|
494 |
// Release the clock
|
|
|
495 |
if (SSP1CON1bits.CKP == 0) {
|
|
|
496 |
SSP1CON1bits.CKP = 1;
|
|
|
497 |
}
|
|
|
498 |
}
|
|
|
499 |
}
|
|
|
500 |
|
|
|
501 |
/* Returns 0 if I2C module is currently busy, otherwise returns status code */
|
|
|
502 |
char I2C_Get_Status() {
|
|
|
503 |
if (data_ptr->operating_mode == I2C_MODE_MASTER) {
|
|
|
504 |
if (data_ptr->master_status != I2C_MASTER_IDLE || data_ptr->buffer_in_len == 0) {
|
|
|
505 |
return 0;
|
|
|
506 |
} else {
|
|
|
507 |
return data_ptr->return_status;
|
|
|
508 |
}
|
|
|
509 |
} else {
|
|
|
510 |
if (data_ptr->operating_state != I2C_IDLE || data_ptr->buffer_in_len == 0) {
|
|
|
511 |
return 0;
|
|
|
512 |
} else {
|
|
|
513 |
return data_ptr->return_status;
|
|
|
514 |
}
|
|
|
515 |
}
|
|
|
516 |
}
|
|
|
517 |
|
|
|
518 |
char I2C_Buffer_Len() {
|
|
|
519 |
return data_ptr->buffer_in_len;
|
|
|
520 |
}
|
|
|
521 |
|
|
|
522 |
/* Returns 0 if I2C module is currently busy, otherwise returns buffer length */
|
|
|
523 |
char I2C_Read_Buffer(char *buffer) {
|
|
|
524 |
char i = 0;
|
|
|
525 |
while (data_ptr->buffer_in_len != 0) {
|
|
|
526 |
buffer[i] = data_ptr->buffer_in[data_ptr->buffer_in_read_ind];
|
|
|
527 |
i++;
|
|
|
528 |
if (data_ptr->buffer_in_read_ind == I2C_BUFFER_SIZE-1) {
|
|
|
529 |
data_ptr->buffer_in_read_ind = 0;
|
|
|
530 |
} else {
|
|
|
531 |
data_ptr->buffer_in_read_ind++;
|
|
|
532 |
}
|
|
|
533 |
data_ptr->buffer_in_len--;
|
|
|
534 |
}
|
|
|
535 |
return i;
|
|
|
536 |
}
|
|
|
537 |
|
|
|
538 |
/* Put data to be returned here */
|
|
|
539 |
char I2C_Process_Send(char c) {
|
|
|
540 |
char ret = 0;
|
|
|
541 |
switch (c) {
|
|
|
542 |
case 0xAA:
|
|
|
543 |
data_ptr->buffer_out[0] = 'A';
|
|
|
544 |
data_ptr->buffer_out_len = 1;
|
|
|
545 |
ret = 1;
|
|
|
546 |
break;
|
|
|
547 |
case 0xBB:
|
|
|
548 |
data_ptr->buffer_out[0] = '1';
|
|
|
549 |
data_ptr->buffer_out[1] = '2';
|
|
|
550 |
data_ptr->buffer_out_len = 2;
|
|
|
551 |
ret = 1;
|
|
|
552 |
break;
|
|
|
553 |
}
|
|
|
554 |
return ret;
|
|
|
555 |
}
|