Skovbrynet
I2C
Fork of
I2C_Debug_for_RealTerm
by 
jim hamblen
main.cpp@0:0c54b73b002c, 2011-03-08 (annotated)
- Committer:
- 4180_1
- Date:
- Tue Mar 08 03:16:34 2011 +0000
- Revision:
- 0:0c54b73b002c
- Child:
- 1:be1498ba7fb4
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| 4180_1 | 0:0c54b73b002c | 1 | #include "mbed.h" |
| 4180_1 | 0:0c54b73b002c | 2 | |
| 4180_1 | 0:0c54b73b002c | 3 | // The program sends and receives I2C commands using RealTerm's I2C tab feature |
| 4180_1 | 0:0c54b73b002c | 4 | // Run Realterm on PC and this program on mbed |
| 4180_1 | 0:0c54b73b002c | 5 | // In RealTerm connect to the mbed's USB virtual COM port |
| 4180_1 | 0:0c54b73b002c | 6 | // Switch to I2C tab |
| 4180_1 | 0:0c54b73b002c | 7 | // Type in I2C address & data to read and write and see the response |
| 4180_1 | 0:0c54b73b002c | 8 | // It is handy to debug complex I2C hardware setups |
| 4180_1 | 0:0c54b73b002c | 9 | // Prints "noack!" when no I2C device responds |
| 4180_1 | 0:0c54b73b002c | 10 | DigitalOut myled(LED1); |
| 4180_1 | 0:0c54b73b002c | 11 | Serial pc(USBTX, USBRX); |
| 4180_1 | 0:0c54b73b002c | 12 | I2C i2c(p9,p10); |
| 4180_1 | 0:0c54b73b002c | 13 | |
| 4180_1 | 0:0c54b73b002c | 14 | char data_length=0; |
| 4180_1 | 0:0c54b73b002c | 15 | int read=0; |
| 4180_1 | 0:0c54b73b002c | 16 | int write=0; |
| 4180_1 | 0:0c54b73b002c | 17 | |
| 4180_1 | 0:0c54b73b002c | 18 | //ugly code structure - should start over and fix this later |
| 4180_1 | 0:0c54b73b002c | 19 | //now that I understand syntax for command strings a bit more - but it works |
| 4180_1 | 0:0c54b73b002c | 20 | // Read in two ASCII characters and convert to a byte |
| 4180_1 | 0:0c54b73b002c | 21 | // ...unless a command character is found |
| 4180_1 | 0:0c54b73b002c | 22 | int getbyte(char *data) { |
| 4180_1 | 0:0c54b73b002c | 23 | char charin=0; |
| 4180_1 | 0:0c54b73b002c | 24 | charin = pc.getc(); |
| 4180_1 | 0:0c54b73b002c | 25 | if (charin == 'R') { |
| 4180_1 | 0:0c54b73b002c | 26 | read=1; |
| 4180_1 | 0:0c54b73b002c | 27 | if (getbyte(&data_length)==0) pc.printf("error"); |
| 4180_1 | 0:0c54b73b002c | 28 | return 2; |
| 4180_1 | 0:0c54b73b002c | 29 | } |
| 4180_1 | 0:0c54b73b002c | 30 | if (charin == 'P') return 3; |
| 4180_1 | 0:0c54b73b002c | 31 | if (charin > 'F') return 0; |
| 4180_1 | 0:0c54b73b002c | 32 | if (charin <='9') charin = charin - '0'; |
| 4180_1 | 0:0c54b73b002c | 33 | else charin = charin +10 - 'A'; |
| 4180_1 | 0:0c54b73b002c | 34 | *data = charin << 4; |
| 4180_1 | 0:0c54b73b002c | 35 | charin = pc.getc(); |
| 4180_1 | 0:0c54b73b002c | 36 | if (charin > 'F') return 0; |
| 4180_1 | 0:0c54b73b002c | 37 | if (charin <='9') charin = charin - '0'; |
| 4180_1 | 0:0c54b73b002c | 38 | else charin = charin +10 - 'A'; |
| 4180_1 | 0:0c54b73b002c | 39 | *data = *data | charin; |
| 4180_1 | 0:0c54b73b002c | 40 | return 1; |
| 4180_1 | 0:0c54b73b002c | 41 | } |
| 4180_1 | 0:0c54b73b002c | 42 | int main() { |
| 4180_1 | 0:0c54b73b002c | 43 | |
| 4180_1 | 0:0c54b73b002c | 44 | char command=0; |
| 4180_1 | 0:0c54b73b002c | 45 | char address=0x40; |
| 4180_1 | 0:0c54b73b002c | 46 | char data[255]; |
| 4180_1 | 0:0c54b73b002c | 47 | char cmd[255]; |
| 4180_1 | 0:0c54b73b002c | 48 | int cmd_count=0; |
| 4180_1 | 0:0c54b73b002c | 49 | int more_cmd = 0; |
| 4180_1 | 0:0c54b73b002c | 50 | int i=0; |
| 4180_1 | 0:0c54b73b002c | 51 | myled=1; |
| 4180_1 | 0:0c54b73b002c | 52 | data[0]=0; |
| 4180_1 | 0:0c54b73b002c | 53 | data[1]=0; |
| 4180_1 | 0:0c54b73b002c | 54 | i2c.frequency(75000); |
| 4180_1 | 0:0c54b73b002c | 55 | i2c.start(); |
| 4180_1 | 0:0c54b73b002c | 56 | i2c.start(); |
| 4180_1 | 0:0c54b73b002c | 57 | pc.printf("\fmbed I2C ready\n\r"); |
| 4180_1 | 0:0c54b73b002c | 58 | // loop forever waiting for PC serial commands |
| 4180_1 | 0:0c54b73b002c | 59 | while (1) { |
| 4180_1 | 0:0c54b73b002c | 60 | command = pc.getc(); |
| 4180_1 | 0:0c54b73b002c | 61 | switch (command) { |
| 4180_1 | 0:0c54b73b002c | 62 | case 'S': |
| 4180_1 | 0:0c54b73b002c | 63 | //Start - automatic start sent on read or write |
| 4180_1 | 0:0c54b73b002c | 64 | data_length=0; |
| 4180_1 | 0:0c54b73b002c | 65 | cmd_count=0; |
| 4180_1 | 0:0c54b73b002c | 66 | read=0; |
| 4180_1 | 0:0c54b73b002c | 67 | write=0; |
| 4180_1 | 0:0c54b73b002c | 68 | // in case of multiple starts |
| 4180_1 | 0:0c54b73b002c | 69 | while (getbyte(&address)==0) {i2c.start();}; |
| 4180_1 | 0:0c54b73b002c | 70 | pc.printf(" - I2C address=%2.2X ", address); |
| 4180_1 | 0:0c54b73b002c | 71 | //odd address means a read, otherwise a write |
| 4180_1 | 0:0c54b73b002c | 72 | if ((address & 0x01) == 1) read=1; |
| 4180_1 | 0:0c54b73b002c | 73 | else write=1; |
| 4180_1 | 0:0c54b73b002c | 74 | if (read ==1) { |
| 4180_1 | 0:0c54b73b002c | 75 | //read number of bytes to read |
| 4180_1 | 0:0c54b73b002c | 76 | if (getbyte(&data_length)==0) break; |
| 4180_1 | 0:0c54b73b002c | 77 | } |
| 4180_1 | 0:0c54b73b002c | 78 | if (write==1) { |
| 4180_1 | 0:0c54b73b002c | 79 | more_cmd =1; |
| 4180_1 | 0:0c54b73b002c | 80 | while (more_cmd==1) { |
| 4180_1 | 0:0c54b73b002c | 81 | if (getbyte(&cmd[cmd_count])>=2) { |
| 4180_1 | 0:0c54b73b002c | 82 | pc.printf(" write "); |
| 4180_1 | 0:0c54b73b002c | 83 | // write I2C command(s) |
| 4180_1 | 0:0c54b73b002c | 84 | if (i2c.write(address, cmd, cmd_count)!=0) pc.printf(" noack! "); |
| 4180_1 | 0:0c54b73b002c | 85 | for (i=0; i<cmd_count; i++) |
| 4180_1 | 0:0c54b73b002c | 86 | pc.printf(" command=%2.2X ", cmd[i]); |
| 4180_1 | 0:0c54b73b002c | 87 | cmd_count=0; |
| 4180_1 | 0:0c54b73b002c | 88 | more_cmd=0; |
| 4180_1 | 0:0c54b73b002c | 89 | write = 0; |
| 4180_1 | 0:0c54b73b002c | 90 | } else cmd_count++; |
| 4180_1 | 0:0c54b73b002c | 91 | } |
| 4180_1 | 0:0c54b73b002c | 92 | if (read==0) pc.printf("\n\r");; |
| 4180_1 | 0:0c54b73b002c | 93 | } |
| 4180_1 | 0:0c54b73b002c | 94 | break; |
| 4180_1 | 0:0c54b73b002c | 95 | case 'P': |
| 4180_1 | 0:0c54b73b002c | 96 | //Stop |
| 4180_1 | 0:0c54b73b002c | 97 | if (read == 1) { |
| 4180_1 | 0:0c54b73b002c | 98 | pc.printf(" read "); |
| 4180_1 | 0:0c54b73b002c | 99 | // read I2C data |
| 4180_1 | 0:0c54b73b002c | 100 | if (i2c.read(address, data, data_length)!=0) pc.printf(" noack! "); |
| 4180_1 | 0:0c54b73b002c | 101 | read = 0; |
| 4180_1 | 0:0c54b73b002c | 102 | write = 0; |
| 4180_1 | 0:0c54b73b002c | 103 | // send I2C data back to PC serial port |
| 4180_1 | 0:0c54b73b002c | 104 | for (i=0; i<data_length; i++) |
| 4180_1 | 0:0c54b73b002c | 105 | pc.printf(" data=%2.2X ",data[i]); |
| 4180_1 | 0:0c54b73b002c | 106 | } |
| 4180_1 | 0:0c54b73b002c | 107 | pc.printf("\n\r"); |
| 4180_1 | 0:0c54b73b002c | 108 | data_length=0; |
| 4180_1 | 0:0c54b73b002c | 109 | cmd_count=0; |
| 4180_1 | 0:0c54b73b002c | 110 | i2c.stop(); |
| 4180_1 | 0:0c54b73b002c | 111 | break; |
| 4180_1 | 0:0c54b73b002c | 112 | case 'R': |
| 4180_1 | 0:0c54b73b002c | 113 | //automatic read after write - read number of bytes to read |
| 4180_1 | 0:0c54b73b002c | 114 | if (getbyte(&data_length)==0) break; |
| 4180_1 | 0:0c54b73b002c | 115 | break; |
| 4180_1 | 0:0c54b73b002c | 116 | case '?': |
| 4180_1 | 0:0c54b73b002c | 117 | //Status |
| 4180_1 | 0:0c54b73b002c | 118 | pc.printf(" mbed ready \n\r"); |
| 4180_1 | 0:0c54b73b002c | 119 | break; |
| 4180_1 | 0:0c54b73b002c | 120 | default: |
| 4180_1 | 0:0c54b73b002c | 121 | |
| 4180_1 | 0:0c54b73b002c | 122 | myled = 0; |
| 4180_1 | 0:0c54b73b002c | 123 | break; |
| 4180_1 | 0:0c54b73b002c | 124 | } |
| 4180_1 | 0:0c54b73b002c | 125 | |
| 4180_1 | 0:0c54b73b002c | 126 | |
| 4180_1 | 0:0c54b73b002c | 127 | } |
| 4180_1 | 0:0c54b73b002c | 128 | } |