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Update analogin_api.c 

Implemented proper self-calibration logic as per UM10732, and changed sampling clock to actually divide by 1 (CLKDIV = 0).
pull/522/head
Neil Thiessen 2014-09-30 12:51:28 -06:00
parent c285cc81bb
commit 14a88d7855
1 changed files with 8 additions and 6 deletions
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14
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11U6X/analogin_api.c
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@ -66,13 +66,15 @@ void analogin_init(analogin_t *obj, PinName pin) {
// Enable clock for ADC
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 13);
// Start ADC self-calibration
LPC_ADC->CTRL = (1UL << 30);
do {
tmp = LPC_ADC->CTRL;
} while ((tmp & (1UL << 30)) != 0);
// Determine the clock divider for a 500kHz ADC clock during calibration
uint32_t clkdiv = (SystemCoreClock / 500000) - 1;
// Perform a self-calibration
LPC_ADC->CTRL = (1UL << 30) | (clkdiv & 0xFF);
while ((LPC_ADC->CTRL & (1UL << 30)) != 0);
LPC_ADC->CTRL = 1; // Sampling clock: SystemClock divided by 1
// Sampling clock: SystemClock divided by 1
LPC_ADC->CTRL = 0;
}
static inline uint32_t adc_read(analogin_t *obj) {