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6. Update the PGA register to enable or disable PGA and configure appropriate gain.
This register is also used to select Power Mode and to check whether the module is
chopper-stabilized.
32.5.1.2 Pseudo-code example
In this example, the ADC module is set up with interrupts enabled to perform a single 10-
bit conversion at low-power with a long sample time on input channel 1, where ADCK is
derived from the bus clock divided by 1.
CFG1 = 0x98 (%10011000)
Bit 7 ADLPC 1 Configures for low power, lowers maximum clock speed.
Bit 6:5 ADIV 00 Sets the ADCK to the input clock ÷ 1.
Bit 4 ADLSMP 1 Configures for long sample time.
Bit 3:2 MODE 10 Selects the single-ended 10-bit conversion, differential 11-
bit conversion.
Bit 1:0 ADICLK 00 Selects the bus clock.
SC2 = 0x00 (%00000000)
Bit 7 ADACT 0 Flag indicates if a conversion is in progress.
Bit 6 ADTRG 0 Software trigger selected.
Bit 5 ACFE 0 Compare function disabled.
Bit 4 ACFGT 0 Not used in this example.
Bit 3 ACREN 0 Compare range disabled.
Bit 2 DMAEN 0 DMA request disabled.
Bit 1:0 REFSEL 00 Selects default voltage reference pin pair (External pins V
REFH
and V
REFL
).
SC1A = 0x41 (%01000001)
Bit 7 COCO 0 Read-only flag which is set when a conversion completes.
Bit 6 AIEN 1 Conversion complete interrupt enabled.
Bit 5 DIFF 0 Single-ended conversion selected.
Bit 4:0 ADCH 00001 Input channel 1 selected as ADC input channel.
RA = 0xxx
Holds results of conversion.
CV = 0xxx
Holds compare value when compare function enabled.
Chapter 32 Analog-to-Digital Converter (ADC)
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
Freescale Semiconductor, Inc.
Preliminary
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