dsPic Receive 11byte usart string - microchip

Question

I'm using a dsPic33 to try and receive a 11-byte string and place it in a array, but have not been successful at receiving it completely. The string I send is "$123456789#" which should be received by the pic. I have tried using the code below. Any help will be appreciated.
char inBytes[11];
int i;
unsigned char temp;
while (U1STAbits.URXDA != 0)
{
temp = U1RXREG;
if (temp == '$')
{
inBytes[0] = temp;
for(i = 1; i < 10; i++)
{
if (U1STAbits.URXDA != 0)
inChar = U1RXREG;
inBytes[i] = inChar;
}
}

Answer 1

jolati had a good point about the end value beeing too low to get 11 bytes but I must add that you have to wait for your other bytes to become available before you read them.
In your example;
char inBytes[11];
int i;
unsigned char temp;
while (!U1STAbits.URXDA ); //Wait until at least one byte is available
temp = U1RXREG;
if (temp == '$')
{
inBytes[0] = temp;
for(i = 1; i < 11; i++) //Loop over range i = 1 to 10 inclusively
{
while (!U1STAbits.URXDA ); //Wait until at least one byte is available
inBytes[i] = U1RXREG;
}
}
Ideally, you would do this in a non blocking way with interrupts so you handle your data as it comes in but, if you cant use interrupts, you can always use non blocking polling like:
void AsyncRX()
{
//Note that the static variables keeps their value between invocations of the
// function. i is set to 0 only on the first run of this function, it keeps
// its value on every other run after that.
static int i = 0;
static char inBytes[11];
//Nothing more to do until there is at least 1 byte available
if( !U1STAbits.URXDA )
return;
//Save the byte and test that our message starts with $
inBytes[i] = U1RXREG;
if( inBytes[0] != '$' )
return;
//Test the counter to see if we have a full 11 bytes
i++;
if( i < 11 )
return;
//Do something with your 11 bytes
//...
//...
//Reset the counter for the next message
i = 0;
}
For the interrupt example, you could simply grab the polled version and throw it into a ISR. The following is an example. Note that I do not know which dsp33 you are using and I have not programmed interrupts in high end cores (with vector tables) in a while so you may need to make a change or two. Also note that you need to enable interupts by setting the appropriate registers as they are not enabled by default.
void __attribute__ ((interrupt, no_auto_psv)) _U1RXInterrupt(void)
{
//Note that the static variables keeps their value between invocations of the
// function. i is set to 0 only on the first run of this function, it keeps
// its value on every other run after that.
static int i = 0;
static char inBytes[11];
//Reset the interrupt flag
IFS0bits.U1RXIF = 0;
//Use up all bytes in the buffer (the interrupt can be set to only fire
// once the buffer has multiple bytes in it).
while( U1STAbits.URXDA )
{
//Save the byte and test that our message starts with $
inBytes[i] = U1RXREG;
if( inBytes[0] != '$' )
continue;
//Test the counter to see if we have a full 11 bytes
i++;
if( i < 11 )
continue;
//Do something with your 11 bytes
//...
//...
//Reset the counter for the next message
i = 0;
}
}

Answer 2

for(i = 1; i < 10; i++) starts saving data at index 1 and stops at 9, only 9 bytes. Change < 10 to <= 10 or < 11.