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STM32L1 Temp Sensor ADC Cycles

Question asked by fisher.burns on Nov 12, 2012
The STM32L1xx datasheet says that the temp sensor sample time will be between 5 and 10 uSec.  The manual confirms this, saying that you should use a 10 uSec sample time.  With the ADC clock running at 16MHz, this would be 160 cycles, but the closes avaialable sample time is 192 cycles.  Right so far?

However, the sample application uses 384 cycles, and in fact if I use only 192, the temperature reading is quite high (using the factory calibration values).  I can use different calibration values, but it seems reading before things stabilize is a bad thing.  I'm doing this as an injected reading, and 384 cycles delays the regular readings too long.

Any ideas about the reliability of using 192 cycles?  It really should be within spec!