Q1 Can you please confirm the TMU_TRITSR[TEMP] and TMU_TRATSR[TEMP] values are reported with precision of 1 degrees Celsius (1 °C) ?
The IMX8MMRM rev 3, 11/2020
Page 776 TMU_TRITSR[7:0] = TEMP[7:0] field description does not indicate the units of measurement.
Q2 Can you please confirm the TMU_TSCR[SENSOR] value is in units of sensor digital counts?
Q3 Can you please confirm to calculate accurate temperature using Tsense=TMU_TRITSR[TEMP], TE1=TSENSOR_VALUE_RT[7:0] and TE2=TSENSOR_VALUE_HT[7:0] in the following formula ?
5.4.5 Temperature Sensor Error Correction Method.
where TE1 and TE2 are the temperature values stored in the 8-bit OTP cells from the
25°C and 85°C measurement, respectively. Units of all terms are degree (°C).
Using real world values I'm reading from the chip
u-boot=>md 0x303504f0 1
303504f0: 013c6636
0x36=TE1 Room Temp 25'C calibration value
0x66=TE2 High Temp 85'C calibration value
-Enable TMU monitoring
u-boot=>mw 0x30260000 0x80000001
-Read TMU_TRITSR
u-boot=>md 0x30260020 1
30260020: 8000003f
-Read TMU_TSCR
u-boot=>md 0x3026001C 1
3026001c: 00000055
Board is sitting at room temperature near 25'C. In the spreadsheet below, the temperature of 36.25 degrees C is closest.
spreadsheet is also attached below.
In other words, Can you please confirm the Tcalib result is the calibrated temperature for use during normal system operation by filling in all Celsius value terms Tsense=TMU_TRITSR[TEMP], TE1=TSENSOR_VALUE_RT[7:0] and TE2=TSENSOR_VALUE_HT[7:0] ?
Q4. Can you please confirm the TMU Sensor Calibration register (TMU_TSCR) register is for NXP internal use only and not expected to be used by developers using the IMX8MM ?
This is because NXP internal manufacturing programs the OTP calibration values at TSENSOR_VALUE_RT and TSENSOR_VALUE_HT previous forum post stated the following with (NXP internal) emphasis added:
Hello,
Generally the calibration points are measured during the (NXP internal) manufacturing testing,
and are programmed in the fuse registers - no need for customers to implement
the calibration.
Regards,
Yuri.
Solved: i.MX8M mini TMU SW calibration code - NXP Community
Hello,
Q1 Can you please confirm the TMU_TRITSR[TEMP] and TMU_TRATSR[TEMP] values are reported with precision of 1 degrees Celsius (1 °C) ?
Sensor has a 1°C of sensing resolution and an accuracy of:
Q2 Can you please confirm the TMU_TSCR[SENSOR] value is in units of sensor digital counts?
Yes, according to internal team TSCR maps to Tsensor.
Q3 Can you please confirm to calculate accurate temperature using Tsense=TMU_TRITSR[TEMP], TE1=TSENSOR_VALUE_RT[7:0] and TE2=TSENSOR_VALUE_HT[7:0] in the following formula?
In other words, Can you please confirm the Tcalib result is the calibrated temperature for use during normal system operation by filling in all Celsius value terms Tsense=TMU_TRITSR[TEMP], TE1=TSENSOR_VALUE_RT[7:0] and TE2=TSENSOR_VALUE_HT[7:0] ?
Yes, that is correct. You could try to see measured temperature on Linux as a reference to compare it with formula result.
Q4. Can you please confirm the TMU Sensor Calibration register (TMU_TSCR) register is for NXP internal use only and not expected to be used by developers using the IMX8MM?
Yes, because these temperature calibration values are part of NXP product testing in site.
Best regards.
Hello,
Q1 Can you please confirm the TMU_TRITSR[TEMP] and TMU_TRATSR[TEMP] values are reported with precision of 1 degrees Celsius (1 °C) ?
Sensor has a 1°C of sensing resolution and an accuracy of:
Q2 Can you please confirm the TMU_TSCR[SENSOR] value is in units of sensor digital counts?
Yes, according to internal team TSCR maps to Tsensor.
Q3 Can you please confirm to calculate accurate temperature using Tsense=TMU_TRITSR[TEMP], TE1=TSENSOR_VALUE_RT[7:0] and TE2=TSENSOR_VALUE_HT[7:0] in the following formula?
In other words, Can you please confirm the Tcalib result is the calibrated temperature for use during normal system operation by filling in all Celsius value terms Tsense=TMU_TRITSR[TEMP], TE1=TSENSOR_VALUE_RT[7:0] and TE2=TSENSOR_VALUE_HT[7:0] ?
Yes, that is correct. You could try to see measured temperature on Linux as a reference to compare it with formula result.
Q4. Can you please confirm the TMU Sensor Calibration register (TMU_TSCR) register is for NXP internal use only and not expected to be used by developers using the IMX8MM?
Yes, because these temperature calibration values are part of NXP product testing in site.
Best regards.
