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126
packetParser.cpp
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126
packetParser.cpp
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#include <string.h>
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#include <Arduino.h>
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#include <SPI.h>
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#if not defined (_VARIANT_ARDUINO_DUE_X_) && not defined (_VARIANT_ARDUINO_ZERO_)
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#include <SoftwareSerial.h>
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#endif
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#include "Adafruit_BLE.h"
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#include "Adafruit_BluefruitLE_SPI.h"
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#include "Adafruit_BluefruitLE_UART.h"
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#define PACKET_PATTERN_LEN (3)
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#define PACKET_COLOR_LEN (6)
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// READ_BUFSIZE Size of the read buffer for incoming packets
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#define READ_BUFSIZE (20)
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/* Buffer to hold incoming characters */
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uint8_t packetbuffer[READ_BUFSIZE+1];
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/**************************************************************************/
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/*!
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@brief Casts the four bytes at the specified address to a float
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*/
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/**************************************************************************/
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float parsefloat(uint8_t *buffer) {
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float f = ((float *)buffer)[0];
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return f;
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}
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/**************************************************************************/
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/*!
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@brief Prints a hexadecimal value in plain characters
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@param data Pointer to the byte data
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@param numBytes Data length in bytes
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*/
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/**************************************************************************/
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void printHex(const uint8_t * data, const uint32_t numBytes)
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{
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uint32_t szPos;
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for (szPos=0; szPos < numBytes; szPos++)
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{
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Serial.print(F("0x"));
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// Append leading 0 for small values
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if (data[szPos] <= 0xF)
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{
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Serial.print(F("0"));
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Serial.print(data[szPos] & 0xf, HEX);
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}
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else
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{
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Serial.print(data[szPos] & 0xff, HEX);
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}
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// Add a trailing space if appropriate
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if ((numBytes > 1) && (szPos != numBytes - 1))
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{
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Serial.print(F(" "));
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}
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}
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Serial.println();
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}
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/**************************************************************************/
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/*!
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@brief Waits for incoming data and parses it
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*/
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/**************************************************************************/
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uint8_t readPacket(Adafruit_BLE *ble, uint16_t timeout)
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{
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uint16_t origtimeout = timeout, replyidx = 0;
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memset(packetbuffer, 0, READ_BUFSIZE);
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while (timeout--) {
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if (replyidx >= 20) break;
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if ((packetbuffer[1] == 'P') && (replyidx == PACKET_PATTERN_LEN))
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break;
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if ((packetbuffer[1] == 'C') && (replyidx == PACKET_COLOR_LEN))
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break;
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while (ble->available()) {
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char c = ble->read();
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if (c == '!') {
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replyidx = 0;
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}
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packetbuffer[replyidx] = c;
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//Serial.print(c);
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replyidx++;
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timeout = origtimeout;
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}
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if (timeout == 0) break;
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delay(1);
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}
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//Serial.println();
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//return;
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packetbuffer[replyidx] = 0; // null term
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if (!replyidx) // no data or timeout
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return 0;
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if (packetbuffer[0] != '!') // doesn't start with '!' packet beginning
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return 0;
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// check checksum!
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uint8_t xsum = 0;
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uint8_t checksum = packetbuffer[replyidx-1];
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for (uint8_t i=0; i<replyidx-1; i++) {
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xsum += packetbuffer[i];
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}
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xsum = ~xsum;
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// Throw an error message if the checksum's don't match
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if (xsum != checksum)
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{
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Serial.print("Checksum mismatch in packet : ");
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printHex(packetbuffer, replyidx+1);
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return 0;
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}
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// checksum passed!
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return replyidx;
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}
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