maple hweeprom.pde

// maple's i2c lib
//   run against i2c eeprom  24LC128   5ms write cycle,  400KHz max
//  http://ww1.microchip.com/downloads/en/devicedoc/21191m.pdf
//    write 1, read 1
//  I2C2 sda,scl PB11,PB10  D30,D29  need pullups

/*
  *  does maple wire lib enable pullups?    left in ground rail
  *   grnd 1    5   3.3v       circle 1  left  notch at top
  *   grnd 2    6   grnd or float
  *   grnd 3    7 SCL  maple 29  4.7K pullup
  *   grnd 4    8 SDA  maple 30  4.7K pullup
  */

#include "i2c.h"
#define I2CID (0xA0 >> 1)

void i2c_eeprom_write_page( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length ) {
    int32 i,err1;
    i2c_msg msgs[1];            // one command
    uint8 msg_data[128];

    msg_data[0] = ((int)(eeaddresspage >> 8)); // MSB
    msg_data[1] = ((int)(eeaddresspage & 0xFF)); // LSB
    for(i=0;i<length;i++) {
        msg_data[i+2] = data[i];
    }
    msgs[0].addr = deviceaddress;
    msgs[0].flags = 0;             // write
    msgs[0].length = length + 2; //  address and data
    msgs[0].data = msg_data;
    err1=i2c_master_xfer(I2C2, msgs, 1,50);  // 1 command  50ms timeout
}

void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte* data, byte length ) {
    int32 err1;
    i2c_msg msgs[2];            // addr command, read command
    uint8 msg_data[2];

    msg_data[0] = ((int)(eeaddress >> 8)); // MSB
    msg_data[1] = ((int)(eeaddress & 0xFF)); // LSB
    msgs[0].addr = deviceaddress;
    msgs[0].flags = 0;     // write addr
    msgs[0].length = 2 ;
    msgs[0].data = msg_data;

    msgs[1].addr = deviceaddress;
    msgs[1].flags = I2C_MSG_READ;     // read
    msgs[1].length = length ;
    msgs[1].data = data;
    err1=i2c_master_xfer(I2C2, msgs, 2,50);  // 2 commands  50ms timeout
  if(err1 != 0) {
    if (err1 == I2C_ERROR_PROTOCOL) {
      SerialUSB.print("Protocol Error Occurred, ");
    }
    else if(err1 == I2C_ERROR_TIMEOUT) {
      SerialUSB.print("Timeout Occurred, ");
    }
    SerialUSB.print("State currently: ");
    SerialUSB.print(I2C2->state,HEX);
    SerialUSB.print(", Error flags: ");
    SerialUSB.println(I2C2->error_flags,HEX);
    // Attempts to recover
    //delayMicroseconds(5);
    //i2c_bus_reset(I2C2);
    //i2c_master_enable(I2C2, I2C_BUS_RESET);
    i2c_disable(I2C2);i2c_master_enable(I2C2, 0);
  }

}


void setup(){
    byte buff[64];
    int i;
    unsigned int t;

    i2c_master_enable(I2C2, 0);  // 100KHz   or I2C_FAST_MODE 400 khz
    while(!SerialUSB.available() ) {
        SerialUSB.println("hit a key");
                delay(1500);
    }
    SerialUSB.read();
    for(i=0;i< sizeof(buff); i++) buff[i]=i+100;

    t=micros();
    i2c_eeprom_write_page(I2CID, 128, buff, sizeof(buff));
    t=micros()-t;
    delay(10);          // time for write to finish, errors otherwise
    SerialUSB.print("blk write ");
    SerialUSB.println(t,DEC);
}

void loop(){
    unsigned int t;
    byte buff[64];

    t=micros();
    i2c_eeprom_read_buffer(I2CID, 0,buff,sizeof(buff));
    t=micros()-t;
    SerialUSB.print("blk read ");
    SerialUSB.println(t,DEC);
    SerialUSB.println((char)buff[1]);
    SerialUSB.println((char)buff[2]);

    i2c_eeprom_read_buffer(I2CID, 128,buff,sizeof(buff));
    SerialUSB.println(buff[1],DEC);
    SerialUSB.println(buff[63],DEC);
    delay(2000);
}