zephyr/drivers/adc/Kconfig.mcux
Johann Fischer 0187d60937 drivers: adc_mcux: improve initialization of the ADC
Improve initialization of the ADC.

After initialization with the default values, the clock source
of the ADC is asynchronous clock (ADACK) and clock divide ratio
is 8. The minimum conversion clock frequency is 1MHz.
Add clock divider selection and set default divide ratio to 1.
That sets the conversion clock frequency to approximately 5MHz.

Default configuration for the voltage reference is set to
external pins V_REFH and V_REFL. Depending on the MCU configuration
V_REFL may be connected to ground and V_REFH to VREF_OUT.
Since Voltage Reference block is not supported, the ADC does not work
properly on FRDM-KW41Z. Add voltage reference selection to fix it.

Enable self-calibration function as recommeded in Reference Manual.

Signed-off-by: Johann Fischer <j.fischer@phytec.de>
2018-12-13 08:32:18 -06:00

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# Kconfig - ADC configuration options
#
# Copyright (c) 2015 Intel Corporation
#
# SPDX-License-Identifier: Apache-2.0
#
config ADC_MCUX_ADC16
bool "MCUX ADC16 driver"
depends on HAS_MCUX_ADC16
help
Enable the MCUX ADC16 driver.
if ADC_MCUX_ADC16
choice
prompt "Clock Divide Selection"
default ADC_MCUX_ADC16_CLK_DIV_RATIO_1
config ADC_MCUX_ADC16_CLK_DIV_RATIO_1
bool "Divide ratio is 1"
config ADC_MCUX_ADC16_CLK_DIV_RATIO_2
bool "Divide ratio is 2"
config ADC_MCUX_ADC16_CLK_DIV_RATIO_4
bool "Divide ratio is 4"
config ADC_MCUX_ADC16_CLK_DIV_RATIO_8
bool "Divide ratio is 8"
endchoice
choice
prompt "Voltage Reference Selection"
default ADC_MCUX_ADC16_VREF_DEFAULT
config ADC_MCUX_ADC16_VREF_DEFAULT
bool "Default voltage reference pair V_REFH and V_REFL"
config ADC_MCUX_ADC16_VREF_ALTERNATE
bool "Alternate reference pair"
endchoice
endif # ADC_MCUX_ADC16