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GR716-DS-UM, May 2019, Version 1.29
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GR716
12.2.5 Low noise sampling
The LEON3FT microcontroller supports low noise sampling i.e. the LEON3FT microcontroller can
disable the LEON3FT processor and peripherals not needed by the system to minimize jitter intro-
duced into the ADC by the LEON3FT microcontroller itself.
To be able to operate or be able to sample and wake-up the application shall:
•
Set the PSR.PIL register low enough for processor to wake-up from expected interrupt
•
Keep clocks enabled for peripherals generating the expected interrupt
Failure to keep expected interrupt source enabled will most likely result in the watch-dog wake-up the
processor.
For low noise sampling the user application shall:
•
Enable ADC clock for channel to use
•
Disable all other interfaces or peripherals not needed in the clock gating unit
•
Enable interrupt generation in ADC or if the DMA is used the DMA controller can be set to gen-
erate the interrupt to wake-up the processor
•
Start sampling and set the LEON3FT microcontroller in power down mode. See 16.1.6
12.2.6 Level Detection
The ADC interface can be configured to monitor the input level. The application can get an event if
the ADC input level is above specified value in register AHT or below the value specified in register
AHL. See table 102 and 103 for register AHT and AHL for the ADC interface.
To enable the level detection and interrupt generation the corresponding bit in the interrupt mask reg-
ister needs to be set. See table 100.
12.2.7 Access control
ADC, Pre-Amplifier and Analog MUX status and configuration can be accessed via registers