diff options
Diffstat (limited to 'sem4/embedded/m3')
| -rw-r--r-- | sem4/embedded/m3/EBNF.txt | 14 | ||||
| -rw-r--r-- | sem4/embedded/m3/m3.ino | 191 |
2 files changed, 205 insertions, 0 deletions
diff --git a/sem4/embedded/m3/EBNF.txt b/sem4/embedded/m3/EBNF.txt new file mode 100644 index 0000000..8c1a81a --- /dev/null +++ b/sem4/embedded/m3/EBNF.txt @@ -0,0 +1,14 @@ +l2frame = 0x02, len, l3packet, checksum, 0x03; +len = byte; +checksum = byte, byte; +l3packet = type, recv_id, transducerl, quiet, nummasters, masters; +recv_id = byte, byte, byte; +transducerl = byte; +quiet = byte; +nummasters = byte; +masters = master | { master }; +master = rssi, txid, txidtime; +rssi = byte; +txid = byte, byte, byte; +txidtime = byte, byte; +byte = 0 | 1 | 2 | ... | 255; diff --git a/sem4/embedded/m3/m3.ino b/sem4/embedded/m3/m3.ino new file mode 100644 index 0000000..235a49e --- /dev/null +++ b/sem4/embedded/m3/m3.ino @@ -0,0 +1,191 @@ + + +void setup() { + Serial.begin(115200); + + Serial.println("Starting the stuff"); + +} + +#define ST_PRE 0 +#define ST_LEN 1 +#define ST_DAT 2 +#define ST_CHK_1 3 +#define ST_CHK_2 4 + +#define P_START 0x02 +#define P_STOP 0x03 +#define P_ESCAPE 0x10 + +#define ESCAPE(c) P_ESCAPE, (uint8_t)c - P_ESCAPE + +struct l2state{ + // See ST_* defines + int state; + // Keeps track of data array. + size_t data_index; + // Whether to interpret next byte as raw. + bool doesc; + // Placeholder for check digits + uint8_t chk[2]; + // Length of data read in layer 2 header + size_t len; +}; + +// Simple test function. Should be replaced with serial.read etc. +uint8_t readnext() { + static size_t index = 0; + uint8_t msg[] = {0, 0, 12, 0x12, 123, 40, 120, 0x02, 13, 1, 2, 2, 0, 88, 50, 1, 90, 5, 0, 0, 88, 2, 74, 216, 0x03, + 0, 0, 0, 0x02, 25, 'A', 0x01, 0, 0, 0x88, ESCAPE(0x10), 3, 23, 0x44, 0, 0, 0xFF, 0xFF, 11, 0xAB, 0, 0, 0xFE, 0xFF, ESCAPE(0x03), 0x40, 0, 0, 0xFF, 0xFF, 50, 125, 0x03, 0, 0, 0, 0}; + + // If we reached the end, stop + if( index > sizeof(msg) / sizeof(uint8_t) ) { + for(;;); + } + return msg[index++ ]; +} + +// Updates checksum vars in s with input +// The flecker algorithm overflows at 254 not 255 +void checksum(struct l2state *s, uint8_t input) { + s->chk[0] = (s->chk[0] + input) % 255; + s->chk[1] = (s->chk[1] + s->chk[0]) % 255; +} + +void l2reset(struct l2state *s) { + s->state = ST_PRE; + memset(s->chk, 0, sizeof(s->chk)); + s->data_index = 0; +} + +// Decodes a single character, returning a value > 0 when finished. +// Remember to zero out s +size_t layer2decode(struct l2state *s, uint8_t *data, uint8_t input) { + /* Commented out because we never check for P_STOP + // Whether to take input as raw with no special meaning. + bool escaped = false; + */ + + // Handle escape + if( s->state && input == P_ESCAPE ) { + s->doesc = true; + return 0; + } + if( s->doesc ) { + input += P_ESCAPE; + s->doesc = false; + //escaped = true; + } + + switch(s->state) { + case ST_PRE: + Serial.print("p"); + // Wait for start. + // Escaped will not be checked because it will always be false here. + if(input == P_START) { + // We are go + s->state = ST_LEN; + } + break; + case ST_LEN: + Serial.print("l"); + // Read a single len, and switch state + s->len = input; + s->state = ST_DAT; + break; + case ST_DAT: + Serial.print("d"); + // Save input as data byte + data[s->data_index++] = input; + + // Update checksum + checksum(s, input); + + // Check if we are done + if(s->data_index >= s->len) { + s->state = ST_CHK_1; + } + break; + case ST_CHK_1: + Serial.print("c1"); + // Check with the one calculated through ST_DAT + if( s->chk[0] != input ) { + Serial.print("Wrong chk1, expected: "); Serial.println(s->chk[0]); + l2reset(s); + break; + } + + s->state = ST_CHK_2; + break; + case ST_CHK_2: + Serial.print("c2"); + if( s->chk[1] != input ) { + Serial.print("Wrong chk2, expected: "); Serial.println(s->chk[1]); + l2reset(s); + // TODO should return error + break; + } + + l2reset(s); + return s->len; + } + + return 0; +} + +struct l3master { + uint8_t rssi; + uint32_t txid : 24; + uint16_t txidtime; +}; + +struct l3pkg { + uint8_t type; + // Arduino is littleendian( LSByte first ). + uint32_t recvid : 24; + // Transducerlevel + uint8_t trslevel; + uint8_t quiettime; + uint8_t nummasters; + struct l3master masters[0]; +}; + +void printl3pkg(struct l3pkg *l3) { + Serial.print("Type :"); Serial.println(l3->type); + Serial.print("Recvid :"); Serial.println(l3->recvid); + Serial.print("Transducerlevel :"); Serial.println(l3->trslevel); + Serial.print("Quiettime :"); Serial.println(l3->quiettime); + Serial.print("Masters :"); Serial.println(l3->nummasters); + + // Loop the masters + for(int i = 0; i < l3->nummasters; i++) { + Serial.print("\nMASTER: "); Serial.println(i); + Serial.print(" rssi :"); Serial.println(l3->masters[i].rssi); + Serial.print(" txid :"); Serial.println(l3->masters[i].txid); + Serial.print(" ixidtime :"); Serial.println(l3->masters[i].txidtime); + } +} + +void loop() { + struct l2state s; + // Zero it out + l2reset(&s); + + uint8_t data[256]; + + while(1) { + uint8_t i = readnext(); + + if( layer2decode(&s, data, i) > 0) { + // Finished package decode + Serial.println("DONE"); + + // Cast to the pkg type + Serial.println("DONE"); + struct l3pkg *l3 = (struct l3pkg *)data; + printl3pkg(l3); + + } + + } +} |