I'm trying to get my LPC55S69-EVK board to do ADC conversions, but either I'm too stupid or the documentation is unclear... I would appreciate any help!
There are demo programs for the ADC, I started with lpadc_polling.c as this seems the simplest version. My goal is to read in a differential 16-bit value but I'm lost. Here are my questions:
1) The readme.txt says I should connect a jumper to P15-2 and P15-3. There is nothing there to connect a jumper to, so am I right to assume that I am supposed to solder a connector in the board there?
2) The function Board_InitPins seems to configure Pin23 as ADC 0_0 - I used the pin configuration tool (MCU config tools -> open pins) to also configure Pin 16 as input. I have pasted the generated BOARD_InitPins below, does that look OK?
3) I used the peripherals tool (MCU config tools -> open peripherals) to configure the ADC to make differential measurements with high resolution. I have pasted the relevant code below.
4) To test, I ran the program, with a connection between A0 and A1 on P19, expecting the ADC to produce 0, but it's producing more or less random numbers somewhere between 1900 and 3000.
Any hints as to where I am going wrong would be very much appreciated!
best regards
Martin
Tool-Generated function BOARD_InitPins
void BOARD_InitPins(void)
{
/* Enables the clock for the I/O controller.: Enable Clock. */
CLOCK_EnableClock(kCLOCK_Iocon);
IOCON->PIO[0][16] = ((IOCON->PIO[0][16] &
/* Mask bits to zero which are setting */
(~(IOCON_PIO_FUNC_MASK | IOCON_PIO_MODE_MASK | IOCON_PIO_DIGIMODE_MASK | IOCON_PIO_ASW_MASK)))
/* Selects pin function.
* : PORT016 (pin 14) is configured as ADC0_8. */
| IOCON_PIO_FUNC(PIO0_16_FUNC_ALT0)
/* Selects function mode (on-chip pull-up/pull-down resistor control).
* : Inactive.
* Inactive (no pull-down/pull-up resistor enabled). */
| IOCON_PIO_MODE(PIO0_16_MODE_INACTIVE)
/* Select Digital mode.
* : Disable digital mode.
* Digital input set to 0. */
| IOCON_PIO_DIGIMODE(PIO0_16_DIGIMODE_ANALOG)
/* Analog switch input control.
* : For all pins except PIO0_9, PIO0_11, PIO0_12, PIO0_15, PIO0_18, PIO0_31, PIO1_0 and
* PIO1_9 analog switch is closed (enabled). */
| IOCON_PIO_ASW(PIO0_16_ASW_VALUE1));
const uint32_t port0_pin23_config = (/* Pin is configured as ADC0_0 */
IOCON_PIO_FUNC0 |
/* No addition pin function */
IOCON_PIO_MODE_INACT |
/* Standard mode, output slew rate control is enabled */
IOCON_PIO_SLEW_STANDARD |
/* Input function is not inverted */
IOCON_PIO_INV_DI |
/* Enables analog function */
IOCON_PIO_ANALOG_EN |
/* Open drain is disabled */
IOCON_PIO_OPENDRAIN_DI |
/* Analog switch is closed (enabled) */
IOCON_PIO_ASW_EN);
/* PORT0 PIN23 (coords: 20) is configured as ADC0_0 */
IOCON_PinMuxSet(IOCON, 0U, 23U, port0_pin23_config);
const uint32_t port0_pin29_config = (/* Pin is configured as FC0_RXD_SDA_MOSI_DATA */
IOCON_PIO_FUNC1 |
/* No addition pin function */
IOCON_PIO_MODE_INACT |
/* Standard mode, output slew rate control is enabled */
IOCON_PIO_SLEW_STANDARD |
/* Input function is not inverted */
IOCON_PIO_INV_DI |
/* Enables digital function */
IOCON_PIO_DIGITAL_EN |
/* Open drain is disabled */
IOCON_PIO_OPENDRAIN_DI);
/* PORT0 PIN29 (coords: 92) is configured as FC0_RXD_SDA_MOSI_DATA */
IOCON_PinMuxSet(IOCON, 0U, 29U, port0_pin29_config);
const uint32_t port0_pin30_config = (/* Pin is configured as FC0_TXD_SCL_MISO_WS */
IOCON_PIO_FUNC1 |
/* No addition pin function */
IOCON_PIO_MODE_INACT |
/* Standard mode, output slew rate control is enabled */
IOCON_PIO_SLEW_STANDARD |
/* Input function is not inverted */
IOCON_PIO_INV_DI |
/* Enables digital function */
IOCON_PIO_DIGITAL_EN |
/* Open drain is disabled */
IOCON_PIO_OPENDRAIN_DI);
/* PORT0 PIN30 (coords: 94) is configured as FC0_TXD_SCL_MISO_WS */
IOCON_PinMuxSet(IOCON, 0U, 30U, port0_pin30_config);
}
*********************************** Generated peripherals.c********************
* BE CAREFUL MODIFYING THIS COMMENT - IT IS YAML SETTINGS FOR TOOLS **********/
/* clang-format on */
const lpadc_config_t LPADC_1_config = {
.enableInDozeMode = true,
.conversionAverageMode = kLPADC_ConversionAverage1,
.enableAnalogPreliminary = false,
.powerUpDelay = 0x80,
.referenceVoltageSource = kLPADC_ReferenceVoltageAlt1,
.powerLevelMode = kLPADC_PowerLevelAlt1,
.triggerPriorityPolicy = kLPADC_TriggerPriorityPreemptImmediately,
.enableConvPause = false,
.convPauseDelay = 0,
.FIFO0Watermark = 0,
.FIFO1Watermark = 0
};
lpadc_conv_command_config_t LPADC_1_commandsConfig[1] = {
{
.sampleChannelMode = kLPADC_SampleChannelDiffBothSide,
.channelNumber = 8U,
.chainedNextCommandNumber = 0,
.enableAutoChannelIncrement = false,
.loopCount = 0,
.hardwareAverageMode = kLPADC_HardwareAverageCount1,
.sampleTimeMode = kLPADC_SampleTimeADCK3,
.hardwareCompareMode = kLPADC_HardwareCompareDisabled,
.hardwareCompareValueHigh = 0,
.hardwareCompareValueLow = 0,
.conversionResolutionMode = kLPADC_ConversionResolutionHigh,
.enableWaitTrigger = false
}
};
lpadc_conv_trigger_config_t LPADC_1_triggersConfig[1] = {
{
.targetCommandId = 0,
.delayPower = 0,
.channelAFIFOSelect = 0,
.channelBFIFOSelect = 0,
.priority = 1,
.enableHardwareTrigger = false
}
};
void LPADC_1_init(void) {
/* Initialize LPADC converter */
LPADC_Init(LPADC_1_PERIPHERAL, &LPADC_1_config);
/* Configure conversion command 1. */
LPADC_SetConvCommandConfig(LPADC_1_PERIPHERAL, 1, &LPADC_1_commandsConfig[0]);
/* Configure trigger 0. */
LPADC_SetConvTriggerConfig(LPADC_1_PERIPHERAL, 0, &LPADC_1_triggersConfig[0]);
}
/***********************************************************************************************************************
* Initialization functions
**********************************************************************************************************************/
void BOARD_InitPeripherals(void)
{
/* Initialize components */
LPADC_1_init();
}
/***********************************************************************************************************************
* BOARD_InitBootPeripherals function
**********************************************************************************************************************/
void BOARD_InitBootPeripherals(void)
{
BOARD_InitPeripherals();
}
