1 | // some definitions
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2 | #define SYS_FREQ (20000000L)
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3 | #define PB_FREQ (5000000L) //=SYS_FREQ/FPBDIV
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4 | #define I2C_CLOCK_FREQ (100000L)
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5 | #define nbr_ms_cycles (1E-3 * SYS_FREQ) //1ms / T = n = 1ms *f
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6 | #define i2cchn I2C2A //I2C channel at Pins 5,6
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7 |
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8 | #define BRG_VAL ((PB_FREQ/2/I2C_CLOCK_FREQ)-2)
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9 |
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10 | /* my scratchpad for I2C channel enumeration: - I2C name
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11 | *
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12 | * chn : I2C1A
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13 | * chn : I2C2A
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14 | * chn : I2C3A
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15 | * chn 3 : I2C1
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16 | * chn : I2C2
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17 | */
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18 |
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19 |
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20 | /**
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21 | * The main function does a loop forever, until it gets manually stopped or an error occured.
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22 | * \return This is a program for a microcontroller. There exists no return value, because there exists no operating system.
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23 | */
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24 | int main(void)
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25 | {
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26 | DBINIT();// Initialize debug messages (when supported)
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27 |
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28 | //disable the I2C port before reconfiguring and starting again ???
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29 | I2CEnable(i2cchn, FALSE);
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30 |
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31 | //*Configure
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32 | I2CConfigure(i2cchn, I2C_ENABLE_SLAVE_CLOCK_STRETCHING);
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33 |
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34 | //*SetFrequency
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35 | int actualClock = I2CSetFrequency(i2cchn, PB_FREQ, I2C_CLOCK_FREQ);
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36 | if ( abs(actualClock-I2C_CLOCK_FREQ) > I2C_CLOCK_FREQ/10 )
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37 | {
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38 | DBPRINTF("I2C clock frequency (%ld) error exceeds 10%%\n", actualClock);
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39 | }
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40 |
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41 | //do the work around taken from the errata sheet
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42 | LATGbits.LATG7=0;
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43 | TRISGbits.TRISG7=0;
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44 |
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45 | //*Enable I2C
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46 | I2CEnable(i2cchn, TRUE);
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47 |
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48 | int result;
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49 |
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50 | while(1)
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51 | {
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52 | //check if the I2C bus is idle
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53 | if (I2CBusIsIdle(i2cchn))
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54 | {
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55 | //send a START condition
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56 | result = I2CStart(i2cchn);
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57 | }
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58 |
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59 | //send '0001010' to the bus, in write mode
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60 | int data = (0xA<<1) | 0;
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61 | if (I2CTransmitterIsReady(i2cchn))
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62 | {
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63 | result = I2CSendByte(i2cchn, data);
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64 |
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65 | //wait for the transmission to complete
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66 | while(!I2CTransmissionHasCompleted(i2cchn));
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67 | if (I2CTransmissionHasCompleted(i2cchn))
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68 | {
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69 | DBPRINTF("All the data was sucessfully written to the I²C bus.");
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70 | if (I2CByteWasAcknowledged(i2cchn))
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71 | {
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72 | DBPRINTF("Slave has acknowledged the recieved data.");
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73 | //data send to the Slave is valid, now other operations can follow
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74 |
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75 | }
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76 | }
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77 | }
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78 | I2CStop(i2cchn); //finally send a STOP condition
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79 | }
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80 | }
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