cc3200/mods/pybadc.c - lite/micropython - Linaro Git Browser

 /*
  * This file is part of the Micro Python project, http://micropython.org/
  *
  * The MIT License (MIT)
  *
  * Copyright (c) 2013, 2014 Damien P. George
  * Copyright (c) 2015 Daniel Campora
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include <stdio.h>
 #include <string.h>

 #include "py/mpconfig.h"
 #include "py/nlr.h"
 #include "py/runtime.h"
 #include "py/binary.h"
 #include "py/gc.h"
 #include "py/mperrno.h"
 #include "bufhelper.h"
 #include "inc/hw_types.h"
 #include "inc/hw_adc.h"
 #include "inc/hw_ints.h"
 #include "inc/hw_memmap.h"
 #include "rom_map.h"
 #include "interrupt.h"
 #include "pin.h"
 #include "gpio.h"
 #include "prcm.h"
 #include "adc.h"
 #include "pybadc.h"
 #include "pybpin.h"
 #include "pybsleep.h"
 #include "pins.h"
 #include "mpexception.h"


 /******************************************************************************
  DECLARE CONSTANTS
  ******************************************************************************/
 #define PYB_ADC_NUM_CHANNELS                4

 /******************************************************************************
  DEFINE TYPES
  ******************************************************************************/
 typedef struct {
     mp_obj_base_t base;
     bool enabled;
 } pyb_adc_obj_t;

 typedef struct {
     mp_obj_base_t base;
     pin_obj_t *pin;
     byte channel;
     byte id;
     bool enabled;
 } pyb_adc_channel_obj_t;


 /******************************************************************************
  DECLARE PRIVATE DATA
  ******************************************************************************/
 STATIC pyb_adc_channel_obj_t pyb_adc_channel_obj[PYB_ADC_NUM_CHANNELS] = { {.pin = &pin_GP2, .channel = ADC_CH_0, .id = 0, .enabled = false},
                                                                            {.pin = &pin_GP3, .channel = ADC_CH_1, .id = 1, .enabled = false},
                                                                            {.pin = &pin_GP4, .channel = ADC_CH_2, .id = 2, .enabled = false},
                                                                            {.pin = &pin_GP5, .channel = ADC_CH_3, .id = 3, .enabled = false} };
 STATIC pyb_adc_obj_t pyb_adc_obj = {.enabled = false};

 STATIC const mp_obj_type_t pyb_adc_channel_type;

 /******************************************************************************
  DECLARE PRIVATE FUNCTIONS
  ******************************************************************************/
 STATIC mp_obj_t adc_channel_deinit(mp_obj_t self_in);

 /******************************************************************************
  DEFINE PUBLIC FUNCTIONS
  ******************************************************************************/
 STATIC void pyb_adc_init (pyb_adc_obj_t *self) {
     // enable and configure the timer
     MAP_ADCTimerConfig(ADC_BASE, (1 << 17) - 1);
     MAP_ADCTimerEnable(ADC_BASE);
     // enable the ADC peripheral
     MAP_ADCEnable(ADC_BASE);
     self->enabled = true;
 }

 STATIC void pyb_adc_check_init(void) {
     // not initialized
     if (!pyb_adc_obj.enabled) {
         mp_raise_OSError(MP_EPERM);
     }
 }

 STATIC void pyb_adc_channel_init (pyb_adc_channel_obj_t *self) {
     // the ADC block must be enabled first
     pyb_adc_check_init();
     // configure the pin in analog mode
     pin_config (self->pin, -1, PIN_TYPE_ANALOG, PIN_TYPE_STD, -1, PIN_STRENGTH_2MA);
     // enable the ADC channel
     MAP_ADCChannelEnable(ADC_BASE, self->channel);
     self->enabled = true;
 }

 STATIC void pyb_adc_deinit_all_channels (void) {
     for (int i = 0; i < PYB_ADC_NUM_CHANNELS; i++) {
         adc_channel_deinit(&pyb_adc_channel_obj[i]);
     }
 }

 /******************************************************************************/
 /* Micro Python bindings : adc object                                         */

 STATIC void adc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_adc_obj_t *self = self_in;
     if (self->enabled) {
         mp_printf(print, "ADC(0, bits=12)");
     } else {
         mp_printf(print, "ADC(0)");
     }
 }

 STATIC const mp_arg_t pyb_adc_init_args[] = {
     { MP_QSTR_id,                          MP_ARG_INT, {.u_int = 0} },
     { MP_QSTR_bits,       MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 12} },
 };
 STATIC mp_obj_t adc_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
     // parse args
     mp_map_t kw_args;
     mp_map_init_fixed_table(&kw_args, n_kw, all_args + n_args);
     mp_arg_val_t args[MP_ARRAY_SIZE(pyb_adc_init_args)];
     mp_arg_parse_all(n_args, all_args, &kw_args, MP_ARRAY_SIZE(args), pyb_adc_init_args, args);

     // check the peripheral id
     if (args[0].u_int != 0) {
         mp_raise_OSError(MP_ENODEV);
     }

     // check the number of bits
     if (args[1].u_int != 12) {
         mp_raise_ValueError(mpexception_value_invalid_arguments);
     }

     // setup the object
     pyb_adc_obj_t *self = &pyb_adc_obj;
     self->base.type = &pyb_adc_type;

     // initialize and register with the sleep module
     pyb_adc_init(self);
     pyb_sleep_add ((const mp_obj_t)self, (WakeUpCB_t)pyb_adc_init);
     return self;
 }

 STATIC mp_obj_t adc_init(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     // parse args
     mp_arg_val_t args[MP_ARRAY_SIZE(pyb_adc_init_args) - 1];
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(args), &pyb_adc_init_args[1], args);
     // check the number of bits
     if (args[0].u_int != 12) {
         mp_raise_ValueError(mpexception_value_invalid_arguments);
     }
     pyb_adc_init(pos_args[0]);
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adc_init_obj, 1, adc_init);

 STATIC mp_obj_t adc_deinit(mp_obj_t self_in) {
     pyb_adc_obj_t *self = self_in;
     // first deinit all channels
     pyb_adc_deinit_all_channels();
     MAP_ADCDisable(ADC_BASE);
     self->enabled = false;
     // unregister it with the sleep module
     pyb_sleep_remove ((const mp_obj_t)self);
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_deinit_obj, adc_deinit);

 STATIC mp_obj_t adc_channel(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     STATIC const mp_arg_t pyb_adc_channel_args[] = {
         { MP_QSTR_id,                          MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
         { MP_QSTR_pin,        MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
     };

     // parse args
     mp_arg_val_t args[MP_ARRAY_SIZE(pyb_adc_channel_args)];
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(args), pyb_adc_channel_args, args);

     uint ch_id;
     if (args[0].u_obj != MP_OBJ_NULL) {
         ch_id = mp_obj_get_int(args[0].u_obj);
         if (ch_id >= PYB_ADC_NUM_CHANNELS) {
             mp_raise_ValueError(mpexception_value_invalid_arguments);
         } else if (args[1].u_obj != mp_const_none) {
             uint pin_ch_id = pin_find_peripheral_type (args[1].u_obj, PIN_FN_ADC, 0);
             if (ch_id != pin_ch_id) {
                 mp_raise_ValueError(mpexception_value_invalid_arguments);
             }
         }
     } else {
         ch_id = pin_find_peripheral_type (args[1].u_obj, PIN_FN_ADC, 0);
     }

     // setup the object
     pyb_adc_channel_obj_t *self = &pyb_adc_channel_obj[ch_id];
     self->base.type = &pyb_adc_channel_type;
     pyb_adc_channel_init (self);
     // register it with the sleep module
     pyb_sleep_add ((const mp_obj_t)self, (WakeUpCB_t)pyb_adc_channel_init);
     return self;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adc_channel_obj, 1, adc_channel);

 STATIC const mp_map_elem_t adc_locals_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_init),                (mp_obj_t)&adc_init_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_deinit),              (mp_obj_t)&adc_deinit_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_channel),             (mp_obj_t)&adc_channel_obj },
 };

 STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);

 const mp_obj_type_t pyb_adc_type = {
     { &mp_type_type },
     .name = MP_QSTR_ADC,
     .print = adc_print,
     .make_new = adc_make_new,
     .locals_dict = (mp_obj_t)&adc_locals_dict,
 };

 STATIC void adc_channel_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_adc_channel_obj_t *self = self_in;
     if (self->enabled) {
         mp_printf(print, "ADCChannel(%u, pin=%q)", self->id, self->pin->name);
     } else {
         mp_printf(print, "ADCChannel(%u)", self->id);
     }
 }

 STATIC mp_obj_t adc_channel_init(mp_obj_t self_in) {
     pyb_adc_channel_obj_t *self = self_in;
     // re-enable it
     pyb_adc_channel_init(self);
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_channel_init_obj, adc_channel_init);

 STATIC mp_obj_t adc_channel_deinit(mp_obj_t self_in) {
     pyb_adc_channel_obj_t *self = self_in;

     MAP_ADCChannelDisable(ADC_BASE, self->channel);
     // unregister it with the sleep module
     pyb_sleep_remove ((const mp_obj_t)self);
     self->enabled = false;
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_channel_deinit_obj, adc_channel_deinit);

 STATIC mp_obj_t adc_channel_value(mp_obj_t self_in) {
     pyb_adc_channel_obj_t *self = self_in;
     uint32_t value;

     // the channel must be enabled
     if (!self->enabled) {
         mp_raise_OSError(MP_EPERM);
     }

     // wait until a new value is available
     while (!MAP_ADCFIFOLvlGet(ADC_BASE, self->channel));
     // read the sample
     value = MAP_ADCFIFORead(ADC_BASE, self->channel);
     // the 12 bit sampled value is stored in bits [13:2]
     return MP_OBJ_NEW_SMALL_INT((value & 0x3FFF) >> 2);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_channel_value_obj, adc_channel_value);

 STATIC mp_obj_t adc_channel_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, 0, false);
     return adc_channel_value (self_in);
 }

 STATIC const mp_map_elem_t adc_channel_locals_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_init),                (mp_obj_t)&adc_channel_init_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_deinit),              (mp_obj_t)&adc_channel_deinit_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_value),               (mp_obj_t)&adc_channel_value_obj },
 };

 STATIC MP_DEFINE_CONST_DICT(adc_channel_locals_dict, adc_channel_locals_dict_table);

 STATIC const mp_obj_type_t pyb_adc_channel_type = {
     { &mp_type_type },
     .name = MP_QSTR_ADCChannel,
     .print = adc_channel_print,
     .call = adc_channel_call,
     .locals_dict = (mp_obj_t)&adc_channel_locals_dict,
 };
	/*
	* This file is part of the Micro Python project, http://micropython.org/
	*
	* The MIT License (MIT)
	*
	* Copyright (c) 2013, 2014 Damien P. George
	* Copyright (c) 2015 Daniel Campora
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include <stdio.h>
	#include <string.h>

	#include "py/mpconfig.h"
	#include "py/nlr.h"
	#include "py/runtime.h"
	#include "py/binary.h"
	#include "py/gc.h"
	#include "py/mperrno.h"
	#include "bufhelper.h"
	#include "inc/hw_types.h"
	#include "inc/hw_adc.h"
	#include "inc/hw_ints.h"
	#include "inc/hw_memmap.h"
	#include "rom_map.h"
	#include "interrupt.h"
	#include "pin.h"
	#include "gpio.h"
	#include "prcm.h"
	#include "adc.h"
	#include "pybadc.h"
	#include "pybpin.h"
	#include "pybsleep.h"
	#include "pins.h"
	#include "mpexception.h"


	/******************************************************************************
	DECLARE CONSTANTS
	******************************************************************************/
	#define PYB_ADC_NUM_CHANNELS 4

	/******************************************************************************
	DEFINE TYPES
	******************************************************************************/
	typedef struct {
	mp_obj_base_t base;
	bool enabled;
	} pyb_adc_obj_t;

	typedef struct {
	mp_obj_base_t base;
	pin_obj_t *pin;
	byte channel;
	byte id;
	bool enabled;
	} pyb_adc_channel_obj_t;


	/******************************************************************************
	DECLARE PRIVATE DATA
	******************************************************************************/
	STATIC pyb_adc_channel_obj_t pyb_adc_channel_obj[PYB_ADC_NUM_CHANNELS] = { {.pin = &pin_GP2, .channel = ADC_CH_0, .id = 0, .enabled = false},
	{.pin = &pin_GP3, .channel = ADC_CH_1, .id = 1, .enabled = false},
	{.pin = &pin_GP4, .channel = ADC_CH_2, .id = 2, .enabled = false},
	{.pin = &pin_GP5, .channel = ADC_CH_3, .id = 3, .enabled = false} };
	STATIC pyb_adc_obj_t pyb_adc_obj = {.enabled = false};

	STATIC const mp_obj_type_t pyb_adc_channel_type;

	/******************************************************************************
	DECLARE PRIVATE FUNCTIONS
	******************************************************************************/
	STATIC mp_obj_t adc_channel_deinit(mp_obj_t self_in);

	/******************************************************************************
	DEFINE PUBLIC FUNCTIONS
	******************************************************************************/
	STATIC void pyb_adc_init (pyb_adc_obj_t *self) {
	// enable and configure the timer
	MAP_ADCTimerConfig(ADC_BASE, (1 << 17) - 1);
	MAP_ADCTimerEnable(ADC_BASE);
	// enable the ADC peripheral
	MAP_ADCEnable(ADC_BASE);
	self->enabled = true;
	}

	STATIC void pyb_adc_check_init(void) {
	// not initialized
	if (!pyb_adc_obj.enabled) {
	mp_raise_OSError(MP_EPERM);
	}
	}

	STATIC void pyb_adc_channel_init (pyb_adc_channel_obj_t *self) {
	// the ADC block must be enabled first
	pyb_adc_check_init();
	// configure the pin in analog mode
	pin_config (self->pin, -1, PIN_TYPE_ANALOG, PIN_TYPE_STD, -1, PIN_STRENGTH_2MA);
	// enable the ADC channel
	MAP_ADCChannelEnable(ADC_BASE, self->channel);
	self->enabled = true;
	}

	STATIC void pyb_adc_deinit_all_channels (void) {
	for (int i = 0; i < PYB_ADC_NUM_CHANNELS; i++) {
	adc_channel_deinit(&pyb_adc_channel_obj[i]);
	}
	}

	/******************************************************************************/
	/* Micro Python bindings : adc object */

	STATIC void adc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
	pyb_adc_obj_t *self = self_in;
	if (self->enabled) {
	mp_printf(print, "ADC(0, bits=12)");
	} else {
	mp_printf(print, "ADC(0)");
	}
	}

	STATIC const mp_arg_t pyb_adc_init_args[] = {
	{ MP_QSTR_id, MP_ARG_INT, {.u_int = 0} },
	{ MP_QSTR_bits, MP_ARG_KW_ONLY \| MP_ARG_INT, {.u_int = 12} },
	};
	STATIC mp_obj_t adc_make_new(const mp_obj_type_t type, size_t n_args, size_t n_kw, const mp_obj_t all_args) {
	// parse args
	mp_map_t kw_args;
	mp_map_init_fixed_table(&kw_args, n_kw, all_args + n_args);
	mp_arg_val_t args[MP_ARRAY_SIZE(pyb_adc_init_args)];
	mp_arg_parse_all(n_args, all_args, &kw_args, MP_ARRAY_SIZE(args), pyb_adc_init_args, args);

	// check the peripheral id
	if (args[0].u_int != 0) {
	mp_raise_OSError(MP_ENODEV);
	}

	// check the number of bits
	if (args[1].u_int != 12) {
	mp_raise_ValueError(mpexception_value_invalid_arguments);
	}

	// setup the object
	pyb_adc_obj_t *self = &pyb_adc_obj;
	self->base.type = &pyb_adc_type;

	// initialize and register with the sleep module
	pyb_adc_init(self);
	pyb_sleep_add ((const mp_obj_t)self, (WakeUpCB_t)pyb_adc_init);
	return self;
	}

	STATIC mp_obj_t adc_init(mp_uint_t n_args, const mp_obj_t pos_args, mp_map_t kw_args) {
	// parse args
	mp_arg_val_t args[MP_ARRAY_SIZE(pyb_adc_init_args) - 1];
	mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(args), &pyb_adc_init_args[1], args);
	// check the number of bits
	if (args[0].u_int != 12) {
	mp_raise_ValueError(mpexception_value_invalid_arguments);
	}
	pyb_adc_init(pos_args[0]);
	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adc_init_obj, 1, adc_init);

	STATIC mp_obj_t adc_deinit(mp_obj_t self_in) {
	pyb_adc_obj_t *self = self_in;
	// first deinit all channels
	pyb_adc_deinit_all_channels();
	MAP_ADCDisable(ADC_BASE);
	self->enabled = false;
	// unregister it with the sleep module
	pyb_sleep_remove ((const mp_obj_t)self);
	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_deinit_obj, adc_deinit);

	STATIC mp_obj_t adc_channel(mp_uint_t n_args, const mp_obj_t pos_args, mp_map_t kw_args) {
	STATIC const mp_arg_t pyb_adc_channel_args[] = {
	{ MP_QSTR_id, MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
	{ MP_QSTR_pin, MP_ARG_KW_ONLY \| MP_ARG_OBJ, {.u_obj = mp_const_none} },
	};

	// parse args
	mp_arg_val_t args[MP_ARRAY_SIZE(pyb_adc_channel_args)];
	mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(args), pyb_adc_channel_args, args);

	uint ch_id;
	if (args[0].u_obj != MP_OBJ_NULL) {
	ch_id = mp_obj_get_int(args[0].u_obj);
	if (ch_id >= PYB_ADC_NUM_CHANNELS) {
	mp_raise_ValueError(mpexception_value_invalid_arguments);
	} else if (args[1].u_obj != mp_const_none) {
	uint pin_ch_id = pin_find_peripheral_type (args[1].u_obj, PIN_FN_ADC, 0);
	if (ch_id != pin_ch_id) {
	mp_raise_ValueError(mpexception_value_invalid_arguments);
	}
	}
	} else {
	ch_id = pin_find_peripheral_type (args[1].u_obj, PIN_FN_ADC, 0);
	}

	// setup the object
	pyb_adc_channel_obj_t *self = &pyb_adc_channel_obj[ch_id];
	self->base.type = &pyb_adc_channel_type;
	pyb_adc_channel_init (self);
	// register it with the sleep module
	pyb_sleep_add ((const mp_obj_t)self, (WakeUpCB_t)pyb_adc_channel_init);
	return self;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adc_channel_obj, 1, adc_channel);

	STATIC const mp_map_elem_t adc_locals_dict_table[] = {
	{ MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&adc_init_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&adc_deinit_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_channel), (mp_obj_t)&adc_channel_obj },
	};

	STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);

	const mp_obj_type_t pyb_adc_type = {
	{ &mp_type_type },
	.name = MP_QSTR_ADC,
	.print = adc_print,
	.make_new = adc_make_new,
	.locals_dict = (mp_obj_t)&adc_locals_dict,
	};

	STATIC void adc_channel_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
	pyb_adc_channel_obj_t *self = self_in;
	if (self->enabled) {
	mp_printf(print, "ADCChannel(%u, pin=%q)", self->id, self->pin->name);
	} else {
	mp_printf(print, "ADCChannel(%u)", self->id);
	}
	}

	STATIC mp_obj_t adc_channel_init(mp_obj_t self_in) {
	pyb_adc_channel_obj_t *self = self_in;
	// re-enable it
	pyb_adc_channel_init(self);
	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_channel_init_obj, adc_channel_init);

	STATIC mp_obj_t adc_channel_deinit(mp_obj_t self_in) {
	pyb_adc_channel_obj_t *self = self_in;

	MAP_ADCChannelDisable(ADC_BASE, self->channel);
	// unregister it with the sleep module
	pyb_sleep_remove ((const mp_obj_t)self);
	self->enabled = false;
	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_channel_deinit_obj, adc_channel_deinit);

	STATIC mp_obj_t adc_channel_value(mp_obj_t self_in) {
	pyb_adc_channel_obj_t *self = self_in;
	uint32_t value;

	// the channel must be enabled
	if (!self->enabled) {
	mp_raise_OSError(MP_EPERM);
	}

	// wait until a new value is available
	while (!MAP_ADCFIFOLvlGet(ADC_BASE, self->channel));
	// read the sample
	value = MAP_ADCFIFORead(ADC_BASE, self->channel);
	// the 12 bit sampled value is stored in bits [13:2]
	return MP_OBJ_NEW_SMALL_INT((value & 0x3FFF) >> 2);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_channel_value_obj, adc_channel_value);

	STATIC mp_obj_t adc_channel_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
	mp_arg_check_num(n_args, n_kw, 0, 0, false);
	return adc_channel_value (self_in);
	}

	STATIC const mp_map_elem_t adc_channel_locals_dict_table[] = {
	{ MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&adc_channel_init_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&adc_channel_deinit_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_value), (mp_obj_t)&adc_channel_value_obj },
	};

	STATIC MP_DEFINE_CONST_DICT(adc_channel_locals_dict, adc_channel_locals_dict_table);

	STATIC const mp_obj_type_t pyb_adc_channel_type = {
	{ &mp_type_type },
	.name = MP_QSTR_ADCChannel,
	.print = adc_channel_print,
	.call = adc_channel_call,
	.locals_dict = (mp_obj_t)&adc_channel_locals_dict,
	};