Ran Bao / Mbed 2 deprecated AwsomeStation

Experiment of serial command protocol

Dependencies:   RingBuffer SerialInterfaceProtocol duinotech_16x2_LCD mbed

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CommandPacket.cpp@2:54932809c7b2, 2016-06-09 (annotated)

Committer:
rba90
Date:
Thu Jun 09 12:28:31 2016 +0000
Revision:
2:54932809c7b2
Parent:
0:2ba6a9f316b6
Child:
3:0c4aa3cec685
Add wrapper for protocol

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rba90 0:2ba6a9f316b6 1 #include "CommandPacket.h"
rba90 0:2ba6a9f316b6 2 #include "mbed.h"
rba90 0:2ba6a9f316b6 3
rba90 0:2ba6a9f316b6 4 #define CHECKSUM_DEBUG
rba90 0:2ba6a9f316b6 5
rba90 0:2ba6a9f316b6 6 uint8_t generate_checksum(uint8_t *data, uint8_t length, uint8_t offset)
rba90 0:2ba6a9f316b6 7 {
rba90 0:2ba6a9f316b6 8 uint8_t s = 0;
rba90 0:2ba6a9f316b6 9
rba90 0:2ba6a9f316b6 10 if (data)
rba90 0:2ba6a9f316b6 11 {
rba90 0:2ba6a9f316b6 12 // take the sum of all data bytes preceding checksum field
rba90 0:2ba6a9f316b6 13 for(uint8_t i = 0; i < length; i++)
rba90 0:2ba6a9f316b6 14 {
rba90 0:2ba6a9f316b6 15 s += data[i + offset];
rba90 0:2ba6a9f316b6 16 }
rba90 0:2ba6a9f316b6 17
rba90 0:2ba6a9f316b6 18 // calculate two's complement of the remainder
rba90 0:2ba6a9f316b6 19 s = 0xff - s + 1;
rba90 0:2ba6a9f316b6 20 }
rba90 0:2ba6a9f316b6 21
rba90 0:2ba6a9f316b6 22 return s;
rba90 0:2ba6a9f316b6 23 }
rba90 0:2ba6a9f316b6 24
rba90 0:2ba6a9f316b6 25 uint8_t hexchar_to_uint8(uint8_t ch)
rba90 0:2ba6a9f316b6 26 {
rba90 0:2ba6a9f316b6 27 uint8_t val = 0;
rba90 0:2ba6a9f316b6 28
rba90 0:2ba6a9f316b6 29 if (ch >= '0' && ch <= '9')
rba90 0:2ba6a9f316b6 30 {
rba90 0:2ba6a9f316b6 31 val = ch - '0';
rba90 0:2ba6a9f316b6 32 }
rba90 0:2ba6a9f316b6 33 else if (ch >= 'A' && ch <= 'F')
rba90 0:2ba6a9f316b6 34 {
rba90 0:2ba6a9f316b6 35 val = ch - 'A';
rba90 0:2ba6a9f316b6 36 val += 10;
rba90 0:2ba6a9f316b6 37 }
rba90 0:2ba6a9f316b6 38 else if (ch >= 'a' && ch <= 'f')
rba90 0:2ba6a9f316b6 39 {
rba90 0:2ba6a9f316b6 40 val = ch - 'a';
rba90 0:2ba6a9f316b6 41 val += 10;
rba90 0:2ba6a9f316b6 42 }
rba90 0:2ba6a9f316b6 43
rba90 0:2ba6a9f316b6 44 return val;
rba90 0:2ba6a9f316b6 45 }
rba90 2:54932809c7b2 46
rba90 0:2ba6a9f316b6 47
rba90 0:2ba6a9f316b6 48 bool CommandPacket::verify()
rba90 0:2ba6a9f316b6 49 {
rba90 0:2ba6a9f316b6 50 return checksum == generate_checksum(payload, length);
rba90 0:2ba6a9f316b6 51 }
rba90 0:2ba6a9f316b6 52
rba90 0:2ba6a9f316b6 53 CommandPacket::CommandPacket()
rba90 0:2ba6a9f316b6 54 {
rba90 0:2ba6a9f316b6 55 // reset internal error number
rba90 0:2ba6a9f316b6 56 errno = NO_ERROR;
rba90 0:2ba6a9f316b6 57
rba90 0:2ba6a9f316b6 58 // set public variables
rba90 0:2ba6a9f316b6 59 sflag = '<';
rba90 0:2ba6a9f316b6 60 command = 0x0;
rba90 0:2ba6a9f316b6 61 length = 0x0;
rba90 0:2ba6a9f316b6 62 memset(payload, 0x0, sizeof(payload));
rba90 0:2ba6a9f316b6 63 checksum = 0x0;
rba90 0:2ba6a9f316b6 64 eflag = '>';
rba90 0:2ba6a9f316b6 65 }
rba90 0:2ba6a9f316b6 66
rba90 0:2ba6a9f316b6 67 const char *CommandPacket::getErrorString() const
rba90 0:2ba6a9f316b6 68 {
rba90 0:2ba6a9f316b6 69 return errorString[errno];
rba90 0:2ba6a9f316b6 70 }
rba90 0:2ba6a9f316b6 71
rba90 0:2ba6a9f316b6 72 char *CommandPacket::getErrorCode() const
rba90 0:2ba6a9f316b6 73 {
rba90 0:2ba6a9f316b6 74 // clear error code
rba90 0:2ba6a9f316b6 75 memset(errorCode, 0x0, sizeof(errorCode));
rba90 0:2ba6a9f316b6 76
rba90 0:2ba6a9f316b6 77 // push into buffer
rba90 0:2ba6a9f316b6 78 snprintf(errorCode, sizeof(errorCode), "%c%02x%02x%02x%02x%c",
rba90 0:2ba6a9f316b6 79 sflag,
rba90 0:2ba6a9f316b6 80 0xe0 | (errno & 0x0f),
rba90 0:2ba6a9f316b6 81 0x1,
rba90 0:2ba6a9f316b6 82 command,
rba90 0:2ba6a9f316b6 83 0x0,
rba90 0:2ba6a9f316b6 84 eflag
rba90 0:2ba6a9f316b6 85 );
rba90 0:2ba6a9f316b6 86
rba90 0:2ba6a9f316b6 87 return errorCode;
rba90 0:2ba6a9f316b6 88 }
rba90 2:54932809c7b2 89
rba90 2:54932809c7b2 90 int CommandPacket::serialize(uint8_t *output)
rba90 2:54932809c7b2 91 {
rba90 2:54932809c7b2 92 // create buffer for payload
rba90 2:54932809c7b2 93 uint8_t buffer[length * 2];
rba90 2:54932809c7b2 94 memset(buffer, 0x0, sizeof(buffer));
rba90 2:54932809c7b2 95
rba90 2:54932809c7b2 96 for (int i = 0; i < length; i++)
rba90 2:54932809c7b2 97 {
rba90 2:54932809c7b2 98 sprintf((char *) (buffer + i * 2), "%02X", payload[i]);
rba90 2:54932809c7b2 99 }
rba90 2:54932809c7b2 100
rba90 2:54932809c7b2 101 // assume the user provide output buffer large enough
rba90 2:54932809c7b2 102 sprintf((char *) output, "%c%02X%02X%s%02X%c",
rba90 2:54932809c7b2 103 sflag,
rba90 2:54932809c7b2 104 command,
rba90 2:54932809c7b2 105 length,
rba90 2:54932809c7b2 106 (char *) buffer,
rba90 2:54932809c7b2 107 generate_checksum(payload, length),
rba90 2:54932809c7b2 108 eflag
rba90 2:54932809c7b2 109 );
rba90 2:54932809c7b2 110
rba90 2:54932809c7b2 111 return length;
rba90 2:54932809c7b2 112 }
rba90 2:54932809c7b2 113
rba90 2:54932809c7b2 114
rba90 2:54932809c7b2 115