add SDM120 electricity meter library (only transmit works
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/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library to query measurements from eastron SDM120-ModBus electricity meter (code)
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* @file sensor_sdm120.h
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2016
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* @note peripherals used: USART @ref sensor_sdm120_usart , GPIO @ref sensor_sdm120_gpio
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*/
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdlib.h> // general utilities
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#include <math.h> // mathematical utilities
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/* STM32 (including CM3) libraries */
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#include <libopencm3/stm32/rcc.h> // real-time control clock library
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#include <libopencm3/stm32/gpio.h> // general purpose input output library
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#include <libopencm3/stm32/usart.h> // universal synchronous asynchronous receiver transmitter library
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#include <libopencm3/cm3/nvic.h> // interrupt handler
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#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
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#include "sensor_sdm120.h" // SDM120 electricity meter header and definitions
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#include "global.h" // common methods
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/** @defgroup sensor_psdm120_usart USART peripheral used for communication with electricity meter
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* @{
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*/
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#define SENSOR_SDM120_USART 3 /**< USART peripheral */
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/** @} */
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/** @defgroup sensor_psdm120_gpio GPIO peripheral used for controlling RS-485 adapter
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* @note driver output is enabled on high while receiver output is enabled on low, thus one pin can be used to control both
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* @{
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*/
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#define SENSOR_SDM120_REDE_PORT B /**< GPIO port for RS-485 receiver and driver output enable signal */
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#define SENSOR_SDM120_REDE_PIN 12 /**< GPIO pin for RS-485 receiver and driver output enable signal */
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/** @} */
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/* input and output ring buffer, indexes, and available memory */
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static uint8_t rx_buffer[9] = {0}; /**< buffer for received response (ModBus response messages can be 2+256+2 long but we will only read up to 2 registers) */
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static volatile uint8_t rx_i = 0; /**< current position of read received data */
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static uint8_t tx_buffer[13] = {0}; /**< buffer for request to transmit (ModBus request messages can be 7+256+2 long but we will only write up to 2 registers */
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static volatile uint8_t tx_i = 0; /**< current position of transmitted data */
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static volatile uint8_t tx_size = 0; /**< size of data to transmitted */
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volatile bool sensor_sdm120_measurement_received = false;
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/** SDM120 3xxxx input register start addresses for the measurement types */
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static const uint16_t register_input[] = {
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0x0000, // 30001 voltage (in volts)
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0x0006, // 30007 current (in amperes)
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0x000c, // 30013 active power (in watts)
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0x0012, // 30019 apparent power (in volt amperes)
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0x0018, // 30025 reactive power (in volt amperes reactive)
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0x001e, // 30031 power factor (0-1)
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0x0046, // 30071 frequency (in hertz)
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0x0048, // 30073 import active energy (in kWh)
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0x004a, // 30075 export active energy (in kWh)
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0x004c, // 30077 import reactive energy (in kVArh)
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0x004e, // 30079 export reactive energy (in kVArh)
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0x0156, // 30343 total active energy (in kWh)
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0x0158 // 30345 total reactive energy (in kVArh)
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};
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/** compute CRC for ModBus
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* @note ModBus uses ANSi/IBM 16-bits CRC (with normal polynomial 0x8005, reverse polynomial 0xA001, start value 0xfff)
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* @param[in] buffer data on which to compute the CRC for
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* @param[in] number of byte to compute the CRC for
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* @return computed CRC checksum
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*/
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static uint16_t crc_modbus(uint8_t* buffer, uint8_t size)
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{
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uint16_t crc = 0xffff; // initial value (for ModBus)
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for (uint8_t i=0; i<size; i++) { // go through every byte
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crc ^= (uint16_t)buffer[i]; // XOR byte
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for (uint8_t b=0; b<8; b++) { // go through every bit
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if (crc&0x0001) { // least significant bit is set (we are using the reverse way)
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crc = (crc>>1)^0xA001; // // shift to the right (for the next bit) and XOR with (reverse) polynomial
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} else {
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crc >>= 1; // just shift right (for the next bit)
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}
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}
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}
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return crc;
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}
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void sensor_sdm120_setup(void)
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{
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// enable USART I/O peripheral
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rcc_periph_clock_enable(RCC_AFIO); // enable pin alternate function (USART)
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rcc_periph_clock_enable(USART_PORT_RCC(SENSOR_SDM120_USART)); // enable clock for USART port peripheral
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rcc_periph_clock_enable(USART_RCC(SENSOR_SDM120_USART)); // enable clock for USART peripheral
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gpio_set_mode(USART_PORT(SENSOR_SDM120_USART), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, USART_PIN_TX(SENSOR_SDM120_USART)); // setup GPIO pin USART transmit
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gpio_set_mode(USART_PORT(SENSOR_SDM120_USART), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, USART_PIN_RX(SENSOR_SDM120_USART)); // setup GPIO pin USART receive
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gpio_set(USART_PORT(SENSOR_SDM120_USART), USART_PIN_RX(SENSOR_SDM120_USART)); // pull up to avoid noise when not connected (it will be set low by RS485 chip when RO is enabled)
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// setup USART parameters for electricity meter
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usart_set_baudrate(USART(SENSOR_SDM120_USART), 2400); // get baud rate by scrolling through the measurements on the electricity meter's screen (default 2400)
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usart_set_databits(USART(SENSOR_SDM120_USART), 8);
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usart_set_stopbits(USART(SENSOR_SDM120_USART), USART_STOPBITS_1);
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usart_set_mode(USART(SENSOR_SDM120_USART), USART_MODE_TX_RX);
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usart_set_parity(USART(SENSOR_SDM120_USART), USART_PARITY_NONE); // get parity by scrolling through the measurements on the electricity meter's screen (default none)
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usart_set_flow_control(USART(SENSOR_SDM120_USART), USART_FLOWCONTROL_NONE);
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nvic_enable_irq(USART_IRQ(SENSOR_SDM120_USART)); // enable the USART interrupt
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usart_enable_rx_interrupt(USART(SENSOR_SDM120_USART)); // enable receive interrupt
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usart_enable(USART(SENSOR_SDM120_USART)); // enable USART
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// setup GPIO
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rcc_periph_clock_enable(RCC_GPIO(SENSOR_SDM120_REDE_PORT)); // enable clock for GPIO peripheral
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gpio_set_mode(GPIO(SENSOR_SDM120_REDE_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(SENSOR_SDM120_REDE_PIN)); // setup GPIO pin for receiver and driver output enable pin
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gpio_clear(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN)); // disable driver output and enable receive output
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// reset states
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tx_i = 0;
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tx_size = 0;
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rx_i = 0;
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sensor_sdm120_measurement_received = false;
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}
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void sensor_sdm120_measurement_request(uint8_t address, enum sensor_sdm120_measurement_type_t type)
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{
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if (tx_i!=0) { // transmission is ongoing
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return;
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}
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if (type>=SENSOR_SDM120_MAX) { // invalid type
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return;
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}
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tx_buffer[0] = address; // set slave device address
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tx_buffer[1] = 0x04; // set function to read 3X registers
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tx_buffer[2] = register_input[type]>>8; // set high register address
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tx_buffer[3] = register_input[type]; // set low register address
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tx_buffer[4] = 0; // set high number of registers to read
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tx_buffer[5] = 2; // set low number of register to read (the measurement are encoded using 32 bits IEE745 float, and register hold 16 bits, thus we want to read 2 registers
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uint16_t crc = crc_modbus(tx_buffer, 6); // compute error check
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tx_buffer[6] = crc; // set low error check
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tx_buffer[7] = crc>>8; // set high error check
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tx_size = 8; // set request size
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gpio_set(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN)); // enable driver output and disable receive output
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USART_SR(USART(SENSOR_SDM120_USART)) &= USART_SR_TXE; // clear interrupt flag
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usart_enable_tx_interrupt(USART(SENSOR_SDM120_USART)); // enable interrupt to send other bytes
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usart_send(USART(SENSOR_SDM120_USART),tx_buffer[tx_i++]); // start transmission
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}
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float sensor_sdm120_measurement_decode(void)
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{
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float measurement = 0; //NAN; // decoded measurement to return (invalid in the beginning)
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if (!sensor_sdm120_measurement_received) { // no measurement received
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return NAN;
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} else {
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sensor_sdm120_measurement_received = false; // reset flag
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}
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if (rx_i<5) { // not a complete response (minimum is address, function, size/error, error check low, error check high)
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return NAN;
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}
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if (crc_modbus(rx_buffer,rx_i)) { // checksum error
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return NAN;
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}
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if (rx_buffer[1]&0x80) { // error condition received
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return measurement; // TODO decode the error condition
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} else if (rx_buffer[1]==0x04) { // read 3xxxx input register response received
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if (rx_i<5 || rx_i-5!=tx_buffer[2]) { // wrong response size
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return NAN;
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}
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if (tx_buffer[2]!=4) { // the code only supports reading a measurement on two registers
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return NAN;
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}
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measurement = (float)((tx_buffer[3]<<24)+(tx_buffer[4]<<16)+(tx_buffer[5]<<8)+(tx_buffer[6]<<0)); // decode big endian encoded float measurement value
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measurement = 0;
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} else if (rx_buffer[1]==0x04) { // read 4xxx holding register response received
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// not supported currently
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} else if (rx_buffer[1]==0x10) { // write 4xxx holding register response received
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// not supported currently
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} else { // unknown function response received
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return NAN;
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}
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return measurement;
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}
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/** USART interrupt service routine called when data has been transmitted or received */
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void USART_ISR(SENSOR_SDM120_USART)(void)
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{
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if (usart_get_interrupt_source(USART(SENSOR_SDM120_USART), USART_SR_TXE)) { // data has been transmitted
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if (tx_i<tx_size && tx_i<LENGTH(tx_buffer)) { // not all bytes transmitted
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usart_send(USART(SENSOR_SDM120_USART),tx_buffer[tx_i++]); // transmit next byte (clears flag)
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} else { // request transmitted
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usart_disable_tx_interrupt(USART(SENSOR_SDM120_USART)); // disable transmit interrupt
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USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_TXE; // clear flag
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USART_CR1(USART(SENSOR_SDM120_USART)) |= USART_CR1_TCIE; // enable transfer complete interrupt
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tx_i = 0; // ready for next transmission
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}
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}
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if (usart_get_interrupt_source(USART(SENSOR_SDM120_USART), USART_SR_TC)) { // data has been transmitted
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USART_CR1(USART(SENSOR_SDM120_USART)) |= USART_CR1_TCIE; // disable transfer complete interrupt
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USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_TC; // clear flag
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gpio_clear(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN)); // disable driver output and enable receive output
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tx_i = 0; // ready for next transmission
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}
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if (usart_get_interrupt_source(USART(SENSOR_SDM120_USART), USART_SR_RXNE)) { // data has been received
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led_toggle();
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if (rx_i<LENGTH(rx_buffer)) { // receiving response
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rx_buffer[rx_i++] = usart_recv(USART(SENSOR_SDM120_USART)); // put received byte in buffer (clears flag)
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if (rx_i>=5 && rx_buffer[2]&0x80) { // error condition response received
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sensor_sdm120_measurement_received = true; // notify used response has been received
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} else if (rx_i>=5 && (uint8_t)(rx_i-5)>=rx_buffer[3] && (rx_buffer[2]==0x04 || rx_buffer[2]==0x03)) { // read input or holding register response received
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sensor_sdm120_measurement_received = true; // notify used response has been receive
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} else if (rx_i>=8 && rx_buffer[2]==0x10) { // write holding register response received
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sensor_sdm120_measurement_received = true; // notify used response has been receive
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}
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} else { // buffer full and unknown response received
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rx_i = 0; // clear buffer (not clearing the flag will restart this ISR)
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//USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_RXNE; // clear flag
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}
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}
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}
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