Với suy nghĩ cá nhân của tôi về Structs là cách hiệu quả nhất để gửi nhiều biến khác nhau, tôi đã xây dựng một thư viện để giúp việc gửi các cấu trúc và biến qua serial dễ dàng hơn. Mã nguồn
Trong thư viện này, nó làm cho việc gửi qua nối tiếp dễ dàng. Tôi đã sử dụng với phần cứng và phần mềm nối tiếp. Thông thường, điều này được sử dụng kết hợp với xbee, vì vậy tôi có thể gửi dữ liệu không dây đến và từ robot.
Khi gửi dữ liệu, nó làm cho nó đơn giản vì nó cho phép bạn gửi một biến hoặc một cấu trúc (nó không quan tâm).
Dưới đây là một ví dụ về việc gửi một char đơn giản qua serial:
// Send the variable charVariable over the serial.
// To send the variable you need to pass an instance of the Serial to use,
// a reference to the variable to send, and the size of the variable being sent.
// If you would like you can specify 2 extra arguments at the end which change the
// default prefix and suffix character used when attempting to reconstruct the variable
// on the receiving end. If prefix and suffix character are specified they'll need to
// match on the receiving end otherwise data won't properly be sent across
char charVariable = 'c'; // Define the variable to be sent over the serial
StreamSend::sendObject(Serial, &charVariable, sizeof(charVariable));
// Specify a prefix and suffix character
StreamSend::sendObject(Serial, &charVariable, sizeof(charVariable), 'a', 'z');
Ví dụ về việc gửi một int đơn giản qua serial:
int intVariable = 13496; // Define the int to be sent over the serial
StreamSend::sendObject(xbeeSerial, &intVariable, sizeof(intVariable));
// Specify a prefix and suffix character
StreamSend::sendObject(xbeeSerial, &intVariable, sizeof(intVariable), 'j', 'p');
Ví dụ về việc gửi một cấu trúc qua serial:
// Define the struct to be sent over the serial
struct SIMPLE_STRUCT {
char charVariable;
int intVariable[7];
boolean boolVariable;
};
SIMPLE_STRUCT simpleStruct;
simpleStruct.charVariable = 'z'; // Set the charVariable in the struct to z
// Fill the intVariable array in the struct with numbers 0 through 6
for(int i=0; i<7; i++) {
simpleStruct.intVariable[i] = i;
}
// Send the struct to the object xbeeSerial which is a software serial that was
// defined. Instead of using xbeeSerial you can use Serial which will imply the
// hardware serial, and on a Mega you can specify Serial, Serial1, Serial2, Serial3.
StreamSend::sendObject(xbeeSerial, &simpleStruct, sizeof(simpleStruct));
// Send the same as above with a different prefix and suffix from the default values
// defined in StreamSend. When specifying when prefix and suffix character to send
// you need to make sure that on the receiving end they match otherwise the data
// won't be able to be read on the other end.
StreamSend::sendObject(xbeeSerial, &simpleStruct, sizeof(simpleStruct), '3', 'u');
Nhận ví dụ:
Nhận một char được gửi qua Streamsend:
char charVariable; // Define the variable on where the data will be put
// Read the data from the Serial object an save it into charVariable once
// the data has been received
byte packetResults = StreamSend::receiveObject(Serial, &charVariable, sizeof(charVariable));
// Reconstruct the char coming from the Serial into charVariable that has a custom
// suffix of a and a prefix of z
byte packetResults = StreamSend::receiveObject(Serial, &charVariable, sizeof(charVariable), 'a', 'z');
Nhận một int được gửi qua StreamSend:
int intVariable; // Define the variable on where the data will be put
// Reconstruct the int from xbeeSerial into the variable intVariable
byte packetResults = StreamSend::receiveObject(xbeeSerial, &intVariable, sizeof(intVariable));
// Reconstruct the data into intVariable that was send with a custom prefix
// of j and a suffix of p
byte packetResults = StreamSend::receiveObject(xbeeSerial, &intVariable, sizeof(intVariable), 'j', 'p');
Nhận cấu trúc được gửi qua StreamSend:
// Define the struct that the data will be put
struct SIMPLE_STRUCT {
char charVariable;
int intVariable[7];
boolean boolVariable;
};
SIMPLE_STRUCT simpleStruct; // Create a struct to store the data in
// Reconstruct the data from xbeeSerial into the object simpleStruct
byte packetResults = StreamSend::receiveObject(xbeeSerial, &simpleStruct, sizeof(simpleStruct));
// Reconstruct the data from xbeeSerial into the object simplestruct that has
// a prefix of 3 and a suffix of p
byte packetResults = StreamSend::receiveObject(xbeeSerial, &simpleStruct, sizeof(simpleStruct), '3', 'p');
Khi bạn đọc dữ liệu bằng cách sử dụng, StreamSend::receiveObject()bạn cần biết dữ liệu đó là TỐT, Không tìm thấy hoặc BAD.
Tốt = Thành công
Không tìm thấy = Không tìm thấy ký tự tiền tố trong khung hình được chỉ định
Xấu = Bằng cách nào đó đã tìm thấy một ký tự tiền tố, nhưng dữ liệu không còn nguyên vẹn. Thông thường nó có nghĩa là không có ký tự hậu tố được tìm thấy hoặc dữ liệu không phải là kích thước chính xác.
Kiểm tra tính hợp lệ của dữ liệu:
// Once you call StreamSend::receiveObject() it returns a byte of the status of
// how things went. If you run that though some of the testing functions it'll
// let you know how the transaction went
if(StreamSend::isPacketGood(packetResults)) {
//The Packet was Good
} else {
//The Packet was Bad
}
if(StreamSend::isPacketCorrupt(packetResults)) {
//The Packet was Corrupt
} else {
//The Packet wasn't found or it was Good
}
if(StreamSend::isPacketNotFound(packetResults)) {
//The Packet was not found after Max # of Tries
} else {
//The Packet was Found, but can be corrupt
}
Lớp SteamSend:
#include "Arduino.h"
#ifndef STREAMSEND_H
#define STREAMSEND_H
#define PACKET_NOT_FOUND 0
#define BAD_PACKET 1
#define GOOD_PACKET 2
// Set the Max size of the Serial Buffer or the amount of data you want to send+2
// You need to add 2 to allow the prefix and suffix character space to send.
#define MAX_SIZE 64
class StreamSend {
private:
static int getWrapperSize() { return sizeof(char)*2; }
static byte receiveObject(Stream &ostream, void* ptr, unsigned int objSize, unsigned int loopSize);
static byte receiveObject(Stream &ostream, void* ptr, unsigned int objSize, unsigned int loopSize, char prefixChar, char suffixChar);
static char _prefixChar; // Default value is s
static char _suffixChar; // Default value is e
static int _maxLoopsToWait;
public:
static void sendObject(Stream &ostream, void* ptr, unsigned int objSize);
static void sendObject(Stream &ostream, void* ptr, unsigned int objSize, char prefixChar, char suffixChar);
static byte receiveObject(Stream &ostream, void* ptr, unsigned int objSize);
static byte receiveObject(Stream &ostream, void* ptr, unsigned int objSize, char prefixChar, char suffixChar);
static boolean isPacketNotFound(const byte packetStatus);
static boolean isPacketCorrupt(const byte packetStatus);
static boolean isPacketGood(const byte packetStatus);
static void setPrefixChar(const char value) { _prefixChar = value; }
static void setSuffixChar(const char value) { _suffixChar = value; }
static void setMaxLoopsToWait(const int value) { _maxLoopsToWait = value; }
static const char getPrefixChar() { return _prefixChar; }
static const char getSuffixChar() { return _suffixChar; }
static const int getMaxLoopsToWait() { return _maxLoopsToWait; }
};
//Preset Some Default Variables
//Can be modified when seen fit
char StreamSend::_prefixChar = 's'; // Starting Character before sending any data across the Serial
char StreamSend::_suffixChar = 'e'; // Ending character after all the data is sent
int StreamSend::_maxLoopsToWait = -1; //Set to -1 for size of current Object and wrapper
/**
* sendObject
*
* Converts the Object to bytes and sends it to the stream
*
* @param Stream to send data to
* @param ptr to struct to fill
* @param size of struct
* @param character to send before the data stream (optional)
* @param character to send after the data stream (optional)
*/
void StreamSend::sendObject(Stream &ostream, void* ptr, unsigned int objSize) {
sendObject(ostream, ptr, objSize, _prefixChar, _suffixChar);
}
void StreamSend::sendObject(Stream &ostream, void* ptr, unsigned int objSize, char prefixChar, char suffixChar) {
if(MAX_SIZE >= objSize+getWrapperSize()) { //make sure the object isn't too large
byte * b = (byte *) ptr; // Create a ptr array of the bytes to send
ostream.write((byte)prefixChar); // Write the suffix character to signify the start of a stream
// Loop through all the bytes being send and write them to the stream
for(unsigned int i = 0; i<objSize; i++) {
ostream.write(b[i]); // Write each byte to the stream
}
ostream.write((byte)suffixChar); // Write the prefix character to signify the end of a stream
}
}
/**
* receiveObject
*
* Gets the data from the stream and stores to supplied object
*
* @param Stream to read data from
* @param ptr to struct to fill
* @param size of struct
* @param character to send before the data stream (optional)
* @param character to send after the data stream (optional)
*/
byte StreamSend::receiveObject(Stream &ostream, void* ptr, unsigned int objSize) {
return receiveObject(ostream, ptr, objSize, _prefixChar, _suffixChar);
}
byte StreamSend::receiveObject(Stream &ostream, void* ptr, unsigned int objSize, char prefixChar, char suffixChar) {
return receiveObject(ostream, ptr, objSize, 0, prefixChar, suffixChar);
}
byte StreamSend::receiveObject(Stream &ostream, void* ptr, unsigned int objSize, unsigned int loopSize, char prefixChar, char suffixChar) {
int maxLoops = (_maxLoopsToWait == -1) ? (objSize+getWrapperSize()) : _maxLoopsToWait;
if(loopSize >= maxLoops) {
return PACKET_NOT_FOUND;
}
if(ostream.available() >= (objSize+getWrapperSize())) { // Packet meets minimum size requirement
if(ostream.read() != (byte)prefixChar) {
// Prefix character is not found
// Loop through the code again reading the next char
return receiveObject(ostream, ptr, objSize, loopSize+1, prefixChar, suffixChar);
}
char data[objSize]; //Create a tmp char array of the data from Stream
ostream.readBytes(data, objSize); //Read the # of bytes
memcpy(ptr, data, objSize); //Copy the bytes into the struct
if(ostream.read() != (byte)suffixChar) {
//Suffix character is not found
return BAD_PACKET;
}
return GOOD_PACKET;
}
return PACKET_NOT_FOUND; //Prefix character wasn't found so no packet detected
}
boolean StreamSend::isPacketNotFound(const byte packetStatus) {
return (packetStatus == PACKET_NOT_FOUND);
}
boolean StreamSend::isPacketCorrupt(const byte packetStatus) {
return (packetStatus == BAD_PACKET);
}
boolean StreamSend::isPacketGood(const byte packetStatus) {
return (packetStatus == GOOD_PACKET);
}
#endif