Subversion Repositories minsoc

#include "../support/board.h"
#include "../support/support.h"
#include "i2c.h"
 
int i2c_rd_done, i2c_wr_done;
 
int i2c_pending_write;
 
int i2c_rd_ptr, i2c_wr_ptr;
 
int i2c_buf_overflow;
i2c_type i2c_data[I2C_BUF_LEN];
 
unsigned char start, pointer_write, write_hbyte, write_lbyte, read_hbyte, read_lbyte;
unsigned char cmd_list[5];
unsigned char dat_list[5];
int i2c_index;
int i2c_end;
 
i2c_type * i2c_get(void)
{
    if ( !i2c_rd_done )
        return NULL;
 
    i2c_rd_done--;
 
    int tmp;
    tmp = i2c_rd_ptr;
 
    if (i2c_rd_ptr < I2C_BUF_LEN-1)
        i2c_rd_ptr++; 
    else
        i2c_rd_ptr = 0;
 
    return &i2c_data[tmp];
}
 
void i2c_init(void)
{
    REG8(I2C_BASE+I2C_PRESC_HI) = 0x00;
    REG8(I2C_BASE+I2C_PRESC_LO) = 49;       //100kHz
    REG8(I2C_BASE+I2C_CTR) = I2C_CTR_EN | I2C_CTR_IRQ_EN;
    i2c_rd_done = 0;
    i2c_wr_done = 0;
    i2c_index = 0;
    i2c_wr_ptr = 0;
    i2c_rd_ptr = 0;
    i2c_buf_overflow = 0;
}
 
void i2c_set_ack_lvl(int ack_lvl, int final_ack_lvl)
{
    int ack, final_ack;
 
    ack = ( ack_lvl ) ? I2C_CR_NACK : I2C_CR_ACK;
    final_ack = ( final_ack_lvl ) ? I2C_CR_NACK : I2C_CR_ACK;
 
    start = I2C_CR_STA | I2C_CR_WR | ack;
    pointer_write = I2C_CR_WR | ack;
    write_hbyte = I2C_CR_WR | ack;
    write_lbyte = I2C_CR_WR | I2C_CR_STO | final_ack;
    read_hbyte = I2C_CR_RD | ack;
    read_lbyte = I2C_CR_RD | I2C_CR_STO | final_ack;
}
 
void i2c_byte_transfer(void)
{
    if ( i2c_index > 0 )
        if ( cmd_list[i2c_index-1] == read_hbyte )
            i2c_data[i2c_wr_ptr].data = (REG8(I2C_BASE+I2C_RXR) << 8) & 0xFF00;
 
    REG8(I2C_BASE+I2C_TXR) = dat_list[i2c_index];
    REG8(I2C_BASE+I2C_CR) = cmd_list[i2c_index];
 
    i2c_index++;
}
 
void i2c_irq(void)
{
    REG8(I2C_BASE+I2C_CR) = I2C_CR_CLR_IRQ;
    if (i2c_index <= i2c_end )
        i2c_byte_transfer();
    else
    {
        if ( cmd_list[i2c_index-1] == read_lbyte )
            i2c_data[i2c_wr_ptr].data |= REG8(I2C_BASE+I2C_RXR);
 
        i2c_index = 0;
 
        if ( i2c_pending_write )
            i2c_wr_done = 1;
        else
        {
            if (i2c_wr_ptr < I2C_BUF_LEN-1)
                i2c_wr_ptr++;
            else
                i2c_wr_ptr = 0;
 
            if (i2c_wr_ptr == i2c_rd_ptr+1)
            {
                i2c_rd_done = 1;
                i2c_buf_overflow++;
            }
            else
                i2c_rd_done++;
        }
    }
}
 
int i2c_trans(i2c_mode * mode, i2c_type * data)
{
    if ( i2c_index != 0 )       //if previous command not fully processed, bail out
        return -1;
 
    i2c_wr_done = 0;
 
    int i = 0;
 
    if ( mode->ptr_set || mode->read_write )    //start conditions with pointer set: (write always set ptr)
    {
		dat_list[i] = (data->address << 1) & I2C_TXR_ADR;
		dat_list[i] |= I2C_TXR_W;
		cmd_list[i++] = start;
 
        dat_list[i] = data->pointer;
        cmd_list[i++] = pointer_write;
 
        if ( !mode->read_write )                //REstart for read, NO-REstart for write
        {
            dat_list[i] = (data->address << 1) & I2C_TXR_ADR;
            dat_list[i] |= I2C_TXR_R;
            cmd_list[i++] = start;
        }
    }
    else                    //start conditions with NO pointer set (read only): ONE start
    {
	    dat_list[i] = (data->address << 1) & I2C_TXR_ADR;
	    dat_list[i] |= I2C_TXR_R;
        cmd_list[i++] = start;
    }
 
    if ( mode->byte_word )  //read/write high byte
    {
        dat_list[i] = data->data >> 8;
        cmd_list[i++] = (mode->read_write) ? write_hbyte : read_hbyte;
    }
 
    dat_list[i] = data->data;   //read/write low byte
    cmd_list[i] = (mode->read_write) ? write_lbyte : read_lbyte;
 
    i2c_end = i;
 
    if ( !mode->read_write )    //set data to 0 for read, avoid or implications ((short)data |= byte)
    {
        i2c_data[i2c_wr_ptr] = *data;
        i2c_data[i2c_wr_ptr].data = 0x0000;
    }
 
    i2c_pending_write = mode->read_write;
 
    i2c_index = 0;
    i2c_byte_transfer();
 
    return mode->read_write+1;
}