Other Parts Discussed in Thread: MSPM0L1305, TEST2
Hello,
We have been testing out the internal temperature sensor and can only get it to work as expected when using either the AUTO power down policy for the ADC or sampling very slow (i.e. 1sec).
I was not able to find any examples in the SDK targeting the internal temperature sensor, will this be added in the future?
TARGET:
LP-MSPM0L1306 / MSPM0L1305 - Preliminary silicon.
ADC:
CLKSOURCE: SYSCLK (32MHz), Divider = 8.
Conversion mode = Single, auto-sampling mode, software trigger source,
Conversion memory 0 = Channel 11 (Temp sensor), VREF using internal reference configured to 1.4V.
12-bit resoultion, sample time 125us, no FIFO.
No averaging
VREF:
Internal, 1.4V, BUSCLK (32MHz), no sample-and-hold-mode
In our test setup we wait for 10 ADC samples and then transmit them over UART - so no debugger connected.
Test1: AUTO_POWER_MODE
We start a conversion every 100ms.
ADC Power down mode is set to AUTO
The ADC samples are relatively stable around 1300cnt.
We consider this the expected behavior.
Test2: MANUAL_POWER_MODE
We start a conversion every 100ms.
ADC Power down mode is set to MANUAL
The first ADC sample after POR is around 1300cnt.
Then the rest of the samples are around 700cnt.
We consider this unexpected behavior and would expect same results as in test1, since we never power down the ADC.
Test3: SLOWER_SAMPLING_TIME_250MS
We start a conversion every 250ms.
ADC Power down mode is set to MANUAL
The first ADC sample after POR is around 1300cnt.
Then the rest of the samples are around 900cnt.
Test4: SLOWER_SAMPLING_TIME_500MS
We start a conversion every 500ms.
ADC Power down mode is set to MANUAL
The ADC samples are relatively stable around 1300cnt.
Test5: SLOWER_SAMPLING_TIME_1000MS
We start a conversion every 1000ms.
ADC Power down mode is set to MANUAL
The ADC samples are relatively stable around 1300cnt.
Test5: CHANNEL_15_SUPPLY_MON
Same setup as test 2 - but we swap the ADC channel to 15 to see if the issue is related to ADC in general or just the temp sensor.
We start a conversion every 100ms.
ADC Power down mode is set to MANUAL
The ADC samples are relatively stable around 3200cnt
We are wondering if you can provide an explanation for this - is there something special we need to do for the temperature sensor when power down policy is set to MANUAL?
Can you provide an example for ADC internal temperature sensor measurements with MANUAL power down mode, single conversion mode with internal vref?
