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cpu, cc2538: add low-lever adc driver

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This commit is contained in:
smlng 2017-07-06 13:38:54 +02:00
parent da4f2f6e6e
commit b30d0617aa
3 changed files with 186 additions and 7 deletions
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4
cpu/cc2538/include/cpu_conf.h
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@ -7,7 +7,7 @@
*/
/**
* @addtogroup cpu_cc2538
* @ingroup cpu_cc2538
* @{
*
* @file
@ -35,7 +35,7 @@ extern "C" {
#endif
/**
* @brief ARM Cortex-M specific CPU configuration
* @name ARM Cortex-M specific CPU configuration
* @{
*/
#define CPU_DEFAULT_IRQ_PRIO (1U)

75
cpu/cc2538/include/periph_cpu.h
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@ -160,7 +160,7 @@ typedef struct {
} i2c_conf_t;
/**
* @brief declare needed generic SPI functions
* @name declare needed generic SPI functions
* @{
*/
#define PERIPH_SPI_NEEDS_INIT_CS
@ -170,7 +170,7 @@ typedef struct {
/** @} */
/**
* @brief Override the default GPIO mode settings
* @name Override the default GPIO mode settings
* @{
*/
#define HAVE_GPIO_MODE_T
@ -185,7 +185,7 @@ typedef enum {
/** @} */
/**
* @brief Override SPI mode settings
* @name Override SPI mode settings
* @{
*/
#define HAVE_SPI_MODE_T
@ -198,7 +198,7 @@ typedef enum {
/** @ */
/**
* @brief Override SPI clock settings
* @name Override SPI clock settings
* @{
*/
#define HAVE_SPI_CLK_T
@ -220,7 +220,7 @@ typedef struct {
} spi_clk_conf_t;
/**
* @brief SPI configuration data structure
* @name SPI configuration data structure
* @{
*/
typedef struct {
@ -241,6 +241,71 @@ typedef struct {
uint_fast8_t cfg; /**< timer config word */
} timer_conf_t;
/**
* @name Override resolution options
* @{
*/
#define HAVE_ADC_RES_T
typedef enum {
ADC_RES_6BIT = (0xa00), /**< not supported by hardware */
ADC_RES_7BIT = (0 << 4), /**< ADC resolution: 7 bit */
ADC_RES_8BIT = (0xb00), /**< not supported by hardware */
ADC_RES_9BIT = (1 << 4), /**< ADC resolution: 9 bit */
ADC_RES_10BIT = (2 << 4), /**< ADC resolution: 10 bit */
ADC_RES_12BIT = (3 << 4), /**< ADC resolution: 12 bit */
ADC_RES_14BIT = (0xc00), /**< not supported by hardware */
ADC_RES_16BIT = (0xd00), /**< not supported by hardware */
} adc_res_t;
/** @} */
/**
* @brief ADC configuration wrapper
*/
typedef gpio_t adc_conf_t;
/**
* @name SOC_ADC_ADCCON3 register bit masks
* @{
*/
#define SOC_ADC_ADCCON3_EREF (0x000000C0) /**< Reference voltage for extra */
#define SOC_ADC_ADCCON3_EDIV (0x00000030) /**< Decimation rate for extra */
#define SOC_ADC_ADCCON3_ECH (0x0000000F) /**< Single channel select */
/** @} */
/**
* @name SOC_ADC_ADCCONx registers field values
* @{
*/
#define SOC_ADC_ADCCON_REF_INT (0 << 6) /**< Internal reference */
#define SOC_ADC_ADCCON_REF_EXT (1 << 6) /**< External reference on AIN7 pin */
#define SOC_ADC_ADCCON_REF_AVDD5 (2 << 6) /**< AVDD5 pin */
#define SOC_ADC_ADCCON_REF_DIFF (3 << 6) /**< External reference on AIN6-AIN7 differential input */
#define SOC_ADC_ADCCON_CH_GND (0xC) /**< GND */
/** @} */
/**
* @brief Mask to check end-of-conversion (EOC) bit
*/
#define SOC_ADC_ADCCON1_EOC_MASK (0x80)
/**
* @name Masks for ADC raw data
* @{
*/
#define SOC_ADC_ADCL_MASK (0x000000FC)
#define SOC_ADC_ADCH_MASK (0x000000FF)
/** @} */
/**
* @name Bit shift for data per ADC resolution
* @{
*/
#define SOCADC_7_BIT_RSHIFT (9U) /**< Mask for getting data( 7 bits ENOB) */
#define SOCADC_9_BIT_RSHIFT (7U) /**< Mask for getting data( 9 bits ENOB) */
#define SOCADC_10_BIT_RSHIFT (6U) /**< Mask for getting data(10 bits ENOB) */
#define SOCADC_12_BIT_RSHIFT (4U) /**< Mask for getting data(12 bits ENOB) */
/** @} */
#ifdef __cplusplus
}
#endif

114
cpu/cc2538/periph/adc.c Normal file
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@ -0,0 +1,114 @@
/*
* Copyright (C) 2017 HAW Hamburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_cc2538
* @ingroup drivers_periph_adc
* @{
*
* @file
* @brief Low-level ADC driver implementation
*
* @notice based on TI peripheral drivers library
*
* @author Sebastian Meiling <s@mlng.net>
* @}
*/
#include "board.h"
#include "cpu.h"
#include "periph_conf.h"
#include "periph_cpu.h"
#include "periph/adc.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
int adc_init(adc_t line)
{
if (line >= ADC_NUMOF) {
DEBUG("adc_init: invalid ADC line (%d)!\n", line);
return -1;
}
cc2538_soc_adc_t *adca = SOC_ADC;
/* stop random number generator, and set STSEL = 1 */
adca->cc2538_adc_adccon1.ADCCON1 = 0x3c;
/* disable any DMA, continous ADC settings */
adca->ADCCON2 = 0x0;
/* configure ADC GPIO as analog input */
gpio_init(adc_config[line], IOC_OVERRIDE_ANA);
return 0;
}
int adc_sample(adc_t line, adc_res_t res)
{
/* check if adc line valid */
if (line >= ADC_NUMOF) {
DEBUG("adc_sample: invalid ADC line!\n");
return -1;
}
uint8_t rshift;
/* check if given resolution valid, and set right shift */
switch(res) {
case ADC_RES_7BIT:
rshift = SOCADC_7_BIT_RSHIFT;
break;
case ADC_RES_9BIT:
rshift = SOCADC_9_BIT_RSHIFT;
break;
case ADC_RES_10BIT:
rshift = SOCADC_10_BIT_RSHIFT;
break;
case ADC_RES_12BIT:
rshift = SOCADC_12_BIT_RSHIFT;
break;
default:
DEBUG("adc_sample: invalid resultion!\n");
return -1;
}
/**
* @attention CC2538 ADC supports differential comparision of two analog
* GPIO inputs, hence negative values are possible. RIOT currently allows
* positive ADC output only. Thus, reduce shift by one to compensate and
* get full value range according to ADC resolution. E.g. 10 Bit resultion
* with diff ADC would have [-512,511] range but RIOT expects [0,1023].
*/
rshift--;
cc2538_soc_adc_t *adca = SOC_ADC;
/* configure adc line with parameters and trigger a single conversion*/
uint32_t reg = (adca->ADCCON3) & ~(SOC_ADC_ADCCON3_EREF |
SOC_ADC_ADCCON3_EDIV |
SOC_ADC_ADCCON3_ECH);
adca->ADCCON3 = reg | res | SOC_ADC_ADCCON_REF |
gpio_pp_num(adc_config[line]);
DEBUG("ADCCON1: %"PRIu32" ADCCON2: %"PRIu32" ADCCON3: %"PRIu32"\n",
adca->cc2538_adc_adccon1.ADCCON1, adca->ADCCON2, adca->ADCCON3);
/* Poll/wait until end of conversion */
while ((adca->cc2538_adc_adccon1.ADCCON1 &
SOC_ADC_ADCCON1_EOC_MASK) == 0) {}
/* Read result after conversion completed,
* reading SOC_ADC_ADCH last will clear SOC_ADC_ADCCON1.EOC */
int16_t sample = adca->ADCL & SOC_ADC_ADCL_MASK;
sample |= (adca->ADCH & SOC_ADC_ADCH_MASK) << 8;
/* sample right shifted depending on resolution */
sample = sample >> rshift;
DEBUG("adc_sample: raw value %"PRIi16"\n", sample);
/* FIXME: currently RIOT ADC allows values >0 only */
if (sample < 0) {
sample = 0;
}
return (int)sample;
}