FAQ: About ADC pre-sampling of SPC56EL60

Document created by Online Support Moderator on Dec 26, 2016Last modified by Online Support Moderator on Dec 26, 2016
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Q:

Looking at below table in datasheet I am wondering if only channels 0 and 1 do support pre-sampling. What about the other channels?

 

 

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A:

Pre-sampling works for both ADC (ADC_0 and ADC_1) and for all the 16 channels (16 for each ADC)

 

The pre-sampling registers need to be set correctly:

                External channels 0-8 and 11-14 (PSCR.PREVAL0)

                Internal channels 9, 10 and 15 (PSCR.PREVAL1)

Note: ADC_0/1 channel 9 is reserved for factory test, but nevertheless the pre-sampling works.

 

In attached test code used following configurations are valid for:

  • ADC_0: Ch_0 .. Ch_15
  • ADC_1: Ch_0 .. Ch_15
  • Pre-sampling:
    • ADC_0 = VDD_HV_ADR0
    • ADC_1 = VDD_HV_ADR1
  • PRECONV = 1 // The ADC will perform a pre-sampling followed by a conversion (the sampling is bypassed, so the conversion result is that of the pre-sampled value)

Moreover, it is possible to show the conversion results (VDD=0xFFF in 12 bits) using a PC connection (HYPER TERMINAL), a RS232 cable and the mini module.

 

The communication parameters are:

  • Baud Rate = 19200
  • Data bits = 8
  • Parity = None
  • Stop bit  = 1
  • PAD_LIN0_TXD    PCR = 18
  • PAD_LIN0_RXD   PCR = 19

 
(extracted from ST Online Support Service)

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