static inline int i2c_status(i2c_t *obj) {
return I2C_STAT(obj);
}
//==========================================================================
// The ISR does the actual work. It is not that much work to justify
// putting it in the DSR, and it is also not clear whether this would
// even work. If an error occurs we try to leave the bus in the same
// state as we would if there was no error.
//==========================================================================
static cyg_uint32 lpc2xxx_i2c_isr(cyg_vector_t vec, cyg_addrword_t data)
{
cyg_lpc2xxx_i2c_extra* extra = (cyg_lpc2xxx_i2c_extra*)data;
cyg_uint8 status;
I2C_R8(I2C_STAT(extra), status);
switch(status)
{
case 0x00: // bus error, stop transfer
SET_CON(extra, CON_STO);
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_BUS;
break;
case 0x08: // START sent, send Addr+R/W
case 0x10: // ReSTART sent, send Addr+R/W
CLR_CON(extra, CON_STA);
I2C_W8(I2C_DAT(extra), extra->i2c_addr);
break;
case 0x18: // Addr ACKed, send data
if(extra->i2c_txbuf == NULL)
{
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_BUF;
cyg_drv_interrupt_mask_intunsafe(vec);
cyg_drv_interrupt_acknowledge(vec);
return CYG_ISR_HANDLED | CYG_ISR_CALL_DSR;
}
I2C_W8(I2C_DAT(extra), *extra->i2c_txbuf);
extra->i2c_txbuf++;
break;
case 0x28: // Data ACKed, send more
extra->i2c_count--;
if(extra->i2c_count == 0)
{
extra->i2c_flag = I2C_FLAG_FINISH;
cyg_drv_interrupt_mask_intunsafe(vec);
cyg_drv_interrupt_acknowledge(vec);
return CYG_ISR_HANDLED | CYG_ISR_CALL_DSR;
}
I2C_W8(I2C_DAT(extra), *extra->i2c_txbuf);
extra->i2c_txbuf++;
break;
case 0x50: // Data ACKed, receive more
case 0x58: // Data not ACKed, end reception
if(extra->i2c_rxbuf == NULL)
{
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_BUF;
cyg_drv_interrupt_mask_intunsafe(vec);
cyg_drv_interrupt_acknowledge(vec);
return CYG_ISR_HANDLED | CYG_ISR_CALL_DSR;
}
I2C_R8(I2C_DAT(extra), *extra->i2c_rxbuf);
extra->i2c_rxbuf++;
extra->i2c_count--;
// fall through
case 0x40: // Addr ACKed, receive data
if(status == 0x58 || extra->i2c_count == 0)
{
extra->i2c_flag = I2C_FLAG_FINISH;
cyg_drv_interrupt_mask_intunsafe(vec);
cyg_drv_interrupt_acknowledge(vec);
return CYG_ISR_HANDLED | CYG_ISR_CALL_DSR;
}
if((extra->i2c_count == 1) && extra->i2c_rxnak)
{
CLR_CON(extra, CON_AA);
}
else
{
SET_CON(extra, CON_AA);
}
break;
case 0x20: // Addr not ACKed
case 0x48: // Addr not ACKed
SET_CON(extra, CON_STO); // tranfer failed - force stop
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_ADDR;
cyg_drv_interrupt_mask_intunsafe(vec);
cyg_drv_interrupt_acknowledge(vec);
break;
case 0x30: // Data not ACKed
SET_CON(extra, CON_STO); // tranfer failed - force stop
extra->i2c_count++;
extra->i2c_txbuf--;
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_DATA;
cyg_drv_interrupt_mask_intunsafe(vec);
cyg_drv_interrupt_acknowledge(vec);
return CYG_ISR_HANDLED | CYG_ISR_CALL_DSR;
break;
case 0x38: // Arbitration lost
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_LOST;
break;
default: // lots of unused states
extra->i2c_flag = I2C_FLAG_ERROR | I2C_FLAG_UNK;
break;
} // switch(status)
CLR_CON(extra, CON_SI);
cyg_drv_interrupt_acknowledge(vec);
//
// We need to call the DSR only if there is really something to signal,
// that means only if extra->i2c_flag != 0
//
if (extra->i2c_flag)
{
return CYG_ISR_HANDLED | CYG_ISR_CALL_DSR;
}
else
{
return CYG_ISR_HANDLED;
}
}
