main.cpp

00001 #include "mbed.h"
00002 #include "memory.h"
00003 
00004 DigitalOut aLED(LED1);
00005 Serial pc(USBTX, USBRX); // tx, rx
00006 I2CSlave slave(p28, p27);
00007 
00008 const int SLAVE_ADDRESS = 0x84;
00009 const int I2C_FREQUENCY = 100000;
00010 const int I2C_BUFFER_SIZE = 6;
00011 
00012 enum COMMAND { PUSH, PULL, CLEAR, PRINT };
00013 
00014 #define intToByte(pbytebuff,intval) (*((int*)(pbytebuff)) = intval)
00015 #define byteToInt(pbytebuff,pintval) (*(pintval) = *((int*)(pbytebuff)))
00016 
00017 int main() {
00018     pc.baud(115200);
00019     pc.printf("Size of integer is %d bytes\r\n", sizeof(int));
00020     
00021     // Alive LED
00022     int cAlive = 0;
00023     
00024     // Configure I2C
00025     slave.frequency(I2C_FREQUENCY);
00026     pc.printf("Slave is working @ %dHz\r\n", I2C_FREQUENCY);
00027     slave.address(SLAVE_ADDRESS);
00028     pc.printf("Slave is working @ SLAVE_ADDRESS = 0x%x\r\n", SLAVE_ADDRESS);
00029 
00030     // Setup memory
00031     Memory memory;
00032     pc.printf("Size of memory buffer is %d elements\r\n", Memory::MEMORY_SIZE);
00033     memory.print();
00034     pc.printf("Awaiting commands from master ...\r\n");
00035 
00036     // I2C buffer
00037     char buffer[I2C_BUFFER_SIZE];
00038     
00039     // Internal address pointer
00040     int pointer = 0;
00041     
00042     while (1) {
00043         int rec = slave.receive();
00044         switch (rec) {
00045             case I2CSlave::ReadAddressed:
00046             {
00047                 int value = memory.get(pointer);
00048                 buffer[0] = pointer;
00049                 intToByte(buffer+1, value);
00050                 if (!slave.write(buffer, 5)) {
00051                     pc.printf("Retrieving and sending to master %d@%d\r\n", value, pointer);
00052                 } else {
00053                     pc.printf("Failed to send to master %d@%d\r\n", value, pointer);
00054                 }
00055                 break;
00056             }
00057             case I2CSlave::WriteAddressed:
00058             {
00059                 // First we read the command byte
00060                 int command = slave.read();
00061                 
00062                 // Check the command
00063                 switch (command)
00064                 {
00065                     case PUSH:
00066                         // Expect 5 more bytes [address] [int value]
00067                         if(!slave.read(buffer, 5)) {
00068                             int address = buffer[0];
00069                             int value;
00070                             byteToInt(buffer+1, &value);
00071                             pc.printf("Storing %d@%d\r\n", value, address);
00072                             memory.set(address, value);
00073                         } else {
00074                             pc.printf("PUSH received with missing address/data\r\n");   
00075                         }
00076                         break;
00077                     
00078                     case PULL:
00079                         // Expect 1 more byte [address]
00080                         if(!slave.read(buffer, 1)) {
00081                             int address = buffer[0];
00082                             pc.printf("Setting pointer to %d\r\n", address);
00083                             if (address < Memory::MEMORY_SIZE) {
00084                                 pointer = address;
00085                             } else {
00086                                 pc.printf("Address out of boundary\r\n");    
00087                             }
00088                         } else {
00089                             pc.printf("PULL received with missing address\r\n");   
00090                         }
00091                         break;
00092                     
00093                     case CLEAR:
00094                         pc.printf("Clearing the memory\r\n");    
00095                         memory.reset();
00096                         slave.stop();
00097                         break;
00098                     
00099                     case PRINT:
00100                         memory.print();
00101                         slave.stop();
00102                         break;
00103                     
00104                     default:
00105                         pc.printf("Unknown command byte\r\n");
00106                 }
00107             }
00108         }
00109         
00110         // Clear buffer
00111         for (int i = 0; i < I2C_BUFFER_SIZE; i++) {
00112             buffer[i] = 0;   
00113         }
00114         
00115         // Alive LED
00116         cAlive = (cAlive + 1) % 100000;
00117         if (!cAlive) {
00118             aLED = !aLED;
00119         }
00120     }
00121 }