int imx233_lradc_sense_ext_temperature(int chan, int sensor)
{
#define EXT_TEMP_ACC_COUNT 5
/* setup channel */
imx233_lradc_setup_channel(chan, false, false, 0, sensor);
/* set current source to 300µA */
imx233_lradc_set_temp_isrc(sensor, HW_LRADC_CTRL2__TEMP_ISRC__300uA);
/* read value and accumulate */
int a = 0;
for(int i = 0; i < EXT_TEMP_ACC_COUNT; i++)
{
imx233_lradc_clear_channel(chan);
imx233_lradc_kick_channel(chan);
imx233_lradc_wait_channel(chan);
a += imx233_lradc_read_channel(chan);
}
/* setup channel for small accumulation */
/* set current source to 20µA */
imx233_lradc_set_temp_isrc(sensor, HW_LRADC_CTRL2__TEMP_ISRC__20uA);
/* read value */
int b = 0;
for(int i = 0; i < EXT_TEMP_ACC_COUNT; i++)
{
imx233_lradc_clear_channel(chan);
imx233_lradc_kick_channel(chan);
imx233_lradc_wait_channel(chan);
b += imx233_lradc_read_channel(chan);
}
/* disable sensor current */
imx233_lradc_set_temp_isrc(sensor, HW_LRADC_CTRL2__TEMP_ISRC__0uA);
return (abs(b - a) / EXT_TEMP_ACC_COUNT) * 1104 / 1000;
}
int imx233_lradc_sense_die_temperature(int nmos_chan, int pmos_chan)
{
// mux sensors
__REG_CLR(HW_LRADC_CTRL2) = HW_LRADC_CTRL2__TEMPSENSE_PWD;
imx233_lradc_clear_channel(nmos_chan);
imx233_lradc_clear_channel(pmos_chan);
// schedule both channels
imx233_lradc_kick_channel(nmos_chan);
imx233_lradc_kick_channel(pmos_chan);
// wait completion
imx233_lradc_wait_channel(nmos_chan);
imx233_lradc_wait_channel(pmos_chan);
// mux sensors
__REG_SET(HW_LRADC_CTRL2) = HW_LRADC_CTRL2__TEMPSENSE_PWD;
// do the computation
int diff = imx233_lradc_read_channel(nmos_chan) - imx233_lradc_read_channel(pmos_chan);
// return diff * 1.012 / 4
return (diff * 1012) / 4000;
}
