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mcp3000.h
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mcp3000.h
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/**
* @file PropWare/mcp3000.h
*
* @author David Zemon
* @author Collin Winans
*
* @copyright
* The MIT License (MIT)<br>
* <br>Copyright (c) 2013 David Zemon<br>
* <br>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:<br>
* <br>The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.<br>
* <br>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.
*/
#pragma once
#include <PropWare/PropWare.h>
#include <PropWare/spi.h>
namespace PropWare {
/**
* @brief MCP3004/MCP3008 ADC driver using SPI communication for the Parallax
* Propeller
*
* @note MCP3000 chips uses SPI mode 2 and shifts data MSB first
*/
class MCP3000 {
public:
/** Single-ended channels */
typedef enum {
/** Channel 0 */ CHANNEL_0,
/** Channel 1 */ CHANNEL_1,
/** Channel 2 */ CHANNEL_2,
/** Channel 3 */ CHANNEL_3,
/** Channel 4 (MCP3008 only) */CHANNEL_4,
/** Channel 5 (MCP3008 only) */CHANNEL_5,
/** Channel 6 (MCP3008 only) */CHANNEL_6,
/** Channel 7 (MCP3008 only) */CHANNEL_7,
} Channel;
/** Pseudo-differential pair channels */
typedef enum {
/** CH0+, CH1- */ DIFF_0_1,
/** CH1+, CH0- */ DIFF_1_0,
/** CH2+, CH3- */ DIFF_2_3,
/** CH3+, CH2- */ DIFF_3_2,
/** CH4+, CH5- (MCP3008 only) */DIFF_4_5,
/** CH5+, CH4- (MCP3008 only) */DIFF_5_4,
/** CH6+, CH7- (MCP3008 only) */DIFF_6_7,
/** CH7+, CH6- (MCP3008 only) */DIFF_7_6
} ChannelDiff;
typedef enum {
/** 10-bit ADC, includes MCP3004 and MCP3008 */MCP300x = 11,
/** 12-bit ADC, includes MCP3204 and MCP3208 */MCP320x = 13,
/** 13-bit ADC, includes MCP3304 and MCP3308 */MCP330x = 14
} PartNumber;
public:
/**
* @brief Construction requires an instance of the SPI module; the SPI module does not need to be started
*
* @param[in] *spi Constructed SPI module
* @param[in] cs Pin mask used for chip select
* @param[in] partNumber Determine bit-width of the ADC channels
* @param[in] alwaysSetSPIMode Should every invocation of `read` or `read_diff` set the SPI mode. Setting
* to true is only necessary when multiple devices are connected to the same
* SPI bus and use different SPI modes
*/
MCP3000 (SPI *spi, const PropWare::Pin::Mask cs, MCP3000::PartNumber partNumber,
const bool alwaysSetSPIMode = false)
: m_spi(spi),
m_alwaysSetMode(alwaysSetSPIMode),
m_dataWidth(partNumber) {
this->m_spi->set_mode(SPI_MODE);
this->m_spi->set_bit_mode(SPI_BITMODE);
this->m_cs.set_mask(cs);
this->m_cs.set();
this->m_cs.set_dir(PropWare::Pin::OUT);
}
/**
* @brief Choose whether to always set the SPI mode and bitmode before reading or writing to the ADC;
* Useful when multiple devices are connected to the SPI bus
*
* @param[in] alwaysSetMode For any non-zero value, the SPI modes will always be set before a read or write
* routine
*/
void always_set_spi_mode (const bool alwaysSetMode) {
this->m_alwaysSetMode = alwaysSetMode;
}
/**
* @brief Read a specific channel's data in single-ended mode
*
* @param[in] channel One of MCP_CHANNEL_`x`, where `x` is a number 0 through 3 (or 0 through 7 for the
* MCP3008); Selects the channel to be read
* @return Returns 0 upon success, error code otherwise
*/
uint16_t read (const MCP3000::Channel channel) {
int8_t options;
uint16_t dat;
options = START | SINGLE_ENDED | channel;
// Two dead bits between output and input - see page 19 of datasheet
options <<= 2;
if (this->m_alwaysSetMode) {
this->m_spi->set_mode(MCP3000::SPI_MODE);
this->m_spi->set_bit_mode(MCP3000::SPI_BITMODE);
}
this->m_cs.clear();
this->m_spi->shift_out(OPTION_WIDTH, (uint32_t) options);
dat = (uint16_t) this->m_spi->shift_in(this->m_dataWidth);
this->m_cs.set();
return dat;
}
/**
* @brief Read a specific axis's data in differential mode
*
* @param[in] channels One of DIFF_`x`_`y`, where `x` is a number 0 through 3 (or 0 through 7 for the
* MCP3008) and `y` is `x` + (`x` + 1)%2 (See above defined enum or datasheet for
* details)
*
* @return Returns 0 upon success, error code otherwise
*/
uint16_t read_diff (const MCP3000::ChannelDiff channels) {
int8_t options;
uint16_t dat;
options = START | DIFFERENTIAL | channels;
// Two dead bits between output and input - see page 19 of datasheet
options <<= 2;
if (this->m_alwaysSetMode) {
this->m_spi->set_mode(SPI_MODE);
this->m_spi->set_bit_mode(SPI_BITMODE);
}
this->m_cs.clear();
this->m_spi->shift_out(OPTION_WIDTH, (uint32_t) options);
dat = (uint16_t) this->m_spi->shift_in(this->m_dataWidth);
this->m_cs.set();
return dat;
}
private:
static const SPI::Mode SPI_MODE = SPI::MODE_2;
static const SPI::BitMode SPI_BITMODE = SPI::MSB_FIRST;
static const uint8_t START = BIT_4;
static const uint8_t SINGLE_ENDED = BIT_3;
static const uint8_t DIFFERENTIAL = 0;
static const uint8_t OPTION_WIDTH = 7;
private:
SPI *m_spi;
PropWare::Pin m_cs;
bool m_alwaysSetMode;
uint8_t m_dataWidth;
};
}