simtrace2/firmware/libboard/common/source/boardver_adc.c

93 lines
2.8 KiB
C

/* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "board.h"
#include "boardver_adc.h"
#define UV_PER_LSB ((3300 * 1000) / 4096)
uint32_t adc2uv(uint16_t adc)
{
uint32_t uv = (uint32_t) adc * UV_PER_LSB;
return uv;
}
/***********************************************************************
* ADC for board version detection
***********************************************************************/
#ifdef PIN_VERSION_DET
static int adc_sam3s_reva_errata = 0;
static const Pin pin_version_det = PIN_VERSION_DET;
/* Warning: Don't call this while other code (like the SIM VCC voltage
* reading) is running. The idea is you call this once during board
* startup and cache the result in a (global) variable if you need it
* later throughout the code */
int get_board_version_adc(void)
{
uint32_t chip_arch = CHIPID->CHIPID_CIDR & CHIPID_CIDR_ARCH_Msk;
uint32_t chip_ver = CHIPID->CHIPID_CIDR & CHIPID_CIDR_VERSION_Msk;
uint16_t sample;
uint32_t uv;
PIO_Configure(&pin_version_det, 1);
PMC_EnablePeripheral(ID_ADC);
ADC->ADC_CR |= ADC_CR_SWRST;
if (chip_ver == 0 &&
(chip_arch == CHIPID_CIDR_ARCH_SAM3SxA ||
chip_arch == CHIPID_CIDR_ARCH_SAM3SxB ||
chip_arch == CHIPID_CIDR_ARCH_SAM3SxC)) {
TRACE_INFO("Enabling Rev.A ADC Errata work-around\r\n");
adc_sam3s_reva_errata = 1;
}
if (adc_sam3s_reva_errata) {
/* Errata Work-Around to clear EOCx flags */
volatile uint32_t foo;
int i;
for (i = 0; i < 16; i++)
foo = ADC->ADC_CDR[i];
}
/* Initialize ADC for AD2, fADC=48/24=2MHz */
ADC->ADC_MR = ADC_MR_TRGEN_DIS | ADC_MR_LOWRES_BITS_12 |
ADC_MR_SLEEP_NORMAL | ADC_MR_FWUP_OFF |
ADC_MR_FREERUN_OFF | ADC_MR_PRESCAL(23) |
ADC_MR_STARTUP_SUT8 | ADC_MR_SETTLING(3) |
ADC_MR_ANACH_NONE | ADC_MR_TRACKTIM(4) |
ADC_MR_TRANSFER(1) | ADC_MR_USEQ_NUM_ORDER;
/* enable AD2 channel only */
ADC->ADC_CHER = ADC_CHER_CH2;
/* Make sure we don't use interrupts as that's what the SIM card
* VCC ADC code is using */
ADC->ADC_IER = 0;
NVIC_DisableIRQ(ADC_IRQn);
ADC->ADC_CR |= ADC_CR_START;
/* busy-wait, actually read the value */
do { } while (!(ADC->ADC_ISR & ADC_ISR_EOC2));
/* convert to voltage */
sample = ADC->ADC_CDR[2];
uv = adc2uv(sample);
TRACE_INFO("VERSION_DET ADC=%u => %lu uV\r\n", sample, uv);
/* FIXME: convert to board version based on thresholds */
return 0;
}
#endif /* PIN_VERSION_DET */