241 lines
8.7 KiB
C
241 lines
8.7 KiB
C
/**************************************************************************************************
|
|
Filename: hal_adc.c
|
|
Revised: $Date: 2010-03-12 16:10:36 -0800 (Fri, 12 Mar 2010) $
|
|
Revision: $Revision: 21910 $
|
|
|
|
Description: This file contains the interface to the HAL ADC.
|
|
|
|
|
|
Copyright 2006-2010 Texas Instruments Incorporated. All rights reserved.
|
|
|
|
IMPORTANT: Your use of this Software is limited to those specific rights
|
|
granted under the terms of a software license agreement between the user
|
|
who downloaded the software, his/her employer (which must be your employer)
|
|
and Texas Instruments Incorporated (the "License"). You may not use this
|
|
Software unless you agree to abide by the terms of the License. The License
|
|
limits your use, and you acknowledge, that the Software may not be modified,
|
|
copied or distributed unless embedded on a Texas Instruments microcontroller
|
|
or used solely and exclusively in conjunction with a Texas Instruments radio
|
|
frequency transceiver, which is integrated into your product. Other than for
|
|
the foregoing purpose, you may not use, reproduce, copy, prepare derivative
|
|
works of, modify, distribute, perform, display or sell this Software and/or
|
|
its documentation for any purpose.
|
|
|
|
YOU FURTHER ACKNOWLEDGE AND AGREE THAT THE SOFTWARE AND DOCUMENTATION ARE
|
|
PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED,
|
|
INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, TITLE,
|
|
NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL
|
|
TEXAS INSTRUMENTS OR ITS LICENSORS BE LIABLE OR OBLIGATED UNDER CONTRACT,
|
|
NEGLIGENCE, STRICT LIABILITY, CONTRIBUTION, BREACH OF WARRANTY, OR OTHER
|
|
LEGAL EQUITABLE THEORY ANY DIRECT OR INDIRECT DAMAGES OR EXPENSES
|
|
INCLUDING BUT NOT LIMITED TO ANY INCIDENTAL, SPECIAL, INDIRECT, PUNITIVE
|
|
OR CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF PROCUREMENT
|
|
OF SUBSTITUTE GOODS, TECHNOLOGY, SERVICES, OR ANY CLAIMS BY THIRD PARTIES
|
|
(INCLUDING BUT NOT LIMITED TO ANY DEFENSE THEREOF), OR OTHER SIMILAR COSTS.
|
|
|
|
Should you have any questions regarding your right to use this Software,
|
|
contact Texas Instruments Incorporated at www.TI.com.
|
|
**************************************************************************************************/
|
|
|
|
/**************************************************************************************************
|
|
* INCLUDES
|
|
**************************************************************************************************/
|
|
|
|
#include "hal_adc.h"
|
|
#include "hal_defs.h"
|
|
#include "hal_mcu.h"
|
|
#include "hal_types.h"
|
|
|
|
/**************************************************************************************************
|
|
* CONSTANTS
|
|
**************************************************************************************************/
|
|
#define HAL_ADC_EOC 0x80 /* End of Conversion bit */
|
|
#define HAL_ADC_START 0x40 /* Starts Conversion */
|
|
|
|
#define HAL_ADC_STSEL_EXT 0x00 /* External Trigger */
|
|
#define HAL_ADC_STSEL_FULL 0x10 /* Full Speed, No Trigger */
|
|
#define HAL_ADC_STSEL_T1C0 0x20 /* Timer1, Channel 0 Compare Event Trigger */
|
|
#define HAL_ADC_STSEL_ST 0x30 /* ADCCON1.ST =1 Trigger */
|
|
|
|
#define HAL_ADC_RAND_NORM 0x00 /* Normal Operation */
|
|
#define HAL_ADC_RAND_LFSR 0x04 /* Clock LFSR */
|
|
#define HAL_ADC_RAND_SEED 0x08 /* Seed Modulator */
|
|
#define HAL_ADC_RAND_STOP 0x0c /* Stop Random Generator */
|
|
#define HAL_ADC_RAND_BITS 0x0c /* Bits [3:2] */
|
|
|
|
#define HAL_ADC_DEC_064 0x00 /* Decimate by 64 : 8-bit resolution */
|
|
#define HAL_ADC_DEC_128 0x10 /* Decimate by 128 : 10-bit resolution */
|
|
#define HAL_ADC_DEC_256 0x20 /* Decimate by 256 : 12-bit resolution */
|
|
#define HAL_ADC_DEC_512 0x30 /* Decimate by 512 : 14-bit resolution */
|
|
#define HAL_ADC_DEC_BITS 0x30 /* Bits [5:4] */
|
|
|
|
#define HAL_ADC_STSEL HAL_ADC_STSEL_ST
|
|
#define HAL_ADC_RAND_GEN HAL_ADC_RAND_STOP
|
|
#define HAL_ADC_REF_VOLT HAL_ADC_REF_AVDD
|
|
#define HAL_ADC_DEC_RATE HAL_ADC_DEC_064
|
|
#define HAL_ADC_SCHN HAL_ADC_CHN_VDD3
|
|
#define HAL_ADC_ECHN HAL_ADC_CHN_GND
|
|
|
|
/* ------------------------------------------------------------------------------------------------
|
|
* Local Variables
|
|
* ------------------------------------------------------------------------------------------------
|
|
*/
|
|
|
|
#if (HAL_ADC == TRUE)
|
|
static uint8 adcRef;
|
|
#endif
|
|
|
|
/**************************************************************************************************
|
|
* @fn HalAdcInit
|
|
*
|
|
* @brief Initialize ADC Service
|
|
*
|
|
* @param None
|
|
*
|
|
* @return None
|
|
**************************************************************************************************/
|
|
void HalAdcInit (void)
|
|
{
|
|
#if (HAL_ADC == TRUE)
|
|
adcRef = HAL_ADC_REF_VOLT;
|
|
#endif
|
|
}
|
|
|
|
/**************************************************************************************************
|
|
* @fn HalAdcRead
|
|
*
|
|
* @brief Read the ADC based on given channel and resolution
|
|
*
|
|
* @param channel - channel where ADC will be read
|
|
* @param resolution - the resolution of the value
|
|
*
|
|
* @return 16 bit value of the ADC in offset binary format.
|
|
*
|
|
* Note that the ADC is "bipolar", which means the GND (0V) level is mid-scale.
|
|
* Note2: This function assumes that ADCCON3 contains the voltage reference.
|
|
**************************************************************************************************/
|
|
uint16 HalAdcRead (uint8 channel, uint8 resolution)
|
|
{
|
|
int16 reading = 0;
|
|
|
|
#if (HAL_ADC == TRUE)
|
|
uint8 i, resbits;
|
|
uint8 adcChannel = 1;
|
|
|
|
/*
|
|
* If Analog input channel is AIN0..AIN7, make sure corresponing P0 I/O pin is enabled. The code
|
|
* does NOT disable the pin at the end of this function. I think it is better to leave the pin
|
|
* enabled because the results will be more accurate. Because of the inherent capacitance on the
|
|
* pin, it takes time for the voltage on the pin to charge up to its steady-state level. If
|
|
* HalAdcRead() has to turn on the pin for every conversion, the results may show a lower voltage
|
|
* than actuality because the pin did not have time to fully charge.
|
|
*/
|
|
if (channel < 8)
|
|
{
|
|
for (i=0; i < channel; i++)
|
|
{
|
|
adcChannel <<= 1;
|
|
}
|
|
}
|
|
|
|
/* Enable channel */
|
|
ADCCFG |= adcChannel;
|
|
|
|
/* Convert resolution to decimation rate */
|
|
switch (resolution)
|
|
{
|
|
case HAL_ADC_RESOLUTION_8:
|
|
resbits = HAL_ADC_DEC_064;
|
|
break;
|
|
case HAL_ADC_RESOLUTION_10:
|
|
resbits = HAL_ADC_DEC_128;
|
|
break;
|
|
case HAL_ADC_RESOLUTION_12:
|
|
resbits = HAL_ADC_DEC_256;
|
|
break;
|
|
case HAL_ADC_RESOLUTION_14:
|
|
default:
|
|
resbits = HAL_ADC_DEC_512;
|
|
break;
|
|
}
|
|
|
|
/* writing to this register starts the extra conversion */
|
|
ADCCON3 = channel | resbits | adcRef;
|
|
|
|
/* Wait for the conversion to be done */
|
|
while (!(ADCCON1 & HAL_ADC_EOC));
|
|
|
|
/* Disable channel after done conversion */
|
|
ADCCFG &= (adcChannel ^ 0xFF);
|
|
|
|
/* Read the result */
|
|
reading = (int16) (ADCL);
|
|
reading |= (int16) (ADCH << 8);
|
|
|
|
/* Treat small negative as 0 */
|
|
if (reading < 0)
|
|
reading = 0;
|
|
|
|
switch (resolution)
|
|
{
|
|
case HAL_ADC_RESOLUTION_8:
|
|
reading >>= 8;
|
|
break;
|
|
case HAL_ADC_RESOLUTION_10:
|
|
reading >>= 6;
|
|
break;
|
|
case HAL_ADC_RESOLUTION_12:
|
|
reading >>= 4;
|
|
break;
|
|
case HAL_ADC_RESOLUTION_14:
|
|
default:
|
|
reading >>= 2;
|
|
break;
|
|
}
|
|
#else
|
|
// unused arguments
|
|
(void) channel;
|
|
(void) resolution;
|
|
#endif
|
|
|
|
return ((uint16)reading);
|
|
}
|
|
|
|
/**************************************************************************************************
|
|
* @fn HalAdcSetReference
|
|
*
|
|
* @brief Sets the reference voltage for the ADC and initializes the service
|
|
*
|
|
* @param reference - the reference voltage to be used by the ADC
|
|
*
|
|
* @return none
|
|
*
|
|
**************************************************************************************************/
|
|
void HalAdcSetReference ( uint8 reference )
|
|
{
|
|
#if (HAL_ADC == TRUE)
|
|
adcRef = reference;
|
|
#endif
|
|
}
|
|
|
|
/*********************************************************************
|
|
* @fn HalAdcCheckVdd
|
|
*
|
|
* @brief Check for minimum Vdd specified.
|
|
*
|
|
* @param vdd - The board-specific Vdd reading to check for.
|
|
*
|
|
* @return TRUE if the Vdd measured is greater than the 'vdd' minimum parameter;
|
|
* FALSE if not.
|
|
*
|
|
*********************************************************************/
|
|
bool HalAdcCheckVdd(uint8 vdd)
|
|
{
|
|
ADCCON3 = 0x0F;
|
|
while (!(ADCCON1 & 0x80));
|
|
return (ADCH > vdd);
|
|
}
|
|
|
|
/**************************************************************************************************
|
|
**************************************************************************************************/
|