ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Increase L0 ADC sample time 

With default sampling time, the MBED2 and CI test shield tests would fail
because the stabilization slope of ADC is relatively slow.
ERROR (out:0.8000) - (in:0.7407) = (0.0593)
ERROR (out:0.9000) - (in:0.8354) = (0.0646)
ERROR (out:1.0000) - (in:0.9289) = (0.0711)

This is related to the 10kOhms resistors used to connect Ain to
Aout mounted on the CI shileds, and internal capacitance of L0 targets.
If connecting Ain and Aout with wires, bypassing the resistors, the test
is passed. So we're increasing the sampling time to let the automated
ci shiled tests PASS.

OK    (out:0.8000) - (in:0.7863) = (0.0137)
OK    (out:0.9000) - (in:0.8869) = (0.0131)
OK    (out:1.0000) - (in:0.9844) = (0.0156)
pull/4641/head
Laurent MEUNIER 2017-06-27 10:29:53 +02:00
parent e3e54e5fd3
commit ca26db620b
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
targets/TARGET_STM/TARGET_STM32L0/analogin_api.c
View File

@ -73,7 +73,7 @@ void analogin_init(analogin_t *obj, PinName pin)
AdcHandle.Init.OversamplingMode = DISABLE;
AdcHandle.Init.ClockPrescaler = ADC_CLOCKPRESCALER_PCLK_DIV1;
AdcHandle.Init.Resolution = ADC_RESOLUTION12b;
AdcHandle.Init.SamplingTime = ADC_SAMPLETIME_41CYCLES_5;
AdcHandle.Init.SamplingTime = ADC_SAMPLETIME_239CYCLES_5;
AdcHandle.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
AdcHandle.Init.DataAlign = ADC_DATAALIGN_RIGHT;
AdcHandle.Init.ContinuousConvMode = DISABLE;