int mailbox::receive() {
if(messageStateMachine(arduinoMessageState))
{
receiveCallback();
}
}
void onReceive(void(*receiveCallback)(const void* obj, const char* data), void* obj, const char* data)
{
os_printf("Received %d bytes!\n", strlen(data));
if (receiveCallback != NULL) {
if (obj != NULL)
receiveCallback(obj, data);
}
}
int mailbox::receive() {
//#define DALY 5
unsigned int header[4] = {0}; //header 0 = '$', header[1] = checksum, header[2,3] = message length.
SPI_Class::read(header, 1);
int count = 0;
while(header[0] != '$')
{
count++;
if(count > 255)
break;
}
SPI_Class::read(header+1, 3);
// unsigned int messageLength = 0;
if(header[0] == '$')
{
inboxSize = (header[2] << 8) + header[3];
if(inboxSize > 2048)
{
return; //safety check against ram murder.
}
unsigned int recvChecksum = header[1];
inbox = (char*) realloc(inbox, inboxSize);
//free(inbox);
//inbox = (char*) malloc(inboxSize);
//SPI_Class::read((unsigned int*) inbox, inboxSize);
for(unsigned int i = 0; i < inboxSize; i++)
{
SPI_Class::read((unsigned int *) &inbox[i], 1);
delayMicroseconds(5); //we can potentially overwhelm the arduino with fast reads. Omitting this delay will not break the protocol but it will increase the error rate.
}
//compute checksum here
unsigned int compChecksum = 0;
for(unsigned int i = 0; i < inboxSize; i++)
{
compChecksum += inbox[i];
}
compChecksum &= 0x00FF;
if(compChecksum != recvChecksum)
{
//Serial.println("bad checksum"); //you probably don't want to call the callback on a broken packer, but here it is.
//receiveCallback();
unsigned int thisByte = MB_BAD;
SPI_Class::write(&thisByte,1);
return 0;
}
else
{
unsigned int thisByte = MB_ACK;
SPI_Class::write(&thisByte,1);
receiveCallback();
return 1;
}
}
else
{
//Serial.println("bad header");
return 0;
}
}
