UART recieving using Basic Atom 28 pin plus BOT BOARD II

acidtech · March 6, 2008, 1:56am

clrc,clrf and clrw are assembly commands for PICmicros. You have to use them correctly. “clrc” clears the carry bit. “clrw” clears the W register. “clrf” clears the specified register.

acidtech · March 6, 2008, 1:58am

KB:

'Begin

OnInterrupt extINT, move ’ interrupt triggers from level change (high to low or low to
’ high))
setextint ext_h2l
enable extINT ’ When first bit that is a zero or stop bit is recieved from UART, it
’ enables interrupt
sethserial H9600

temp var byte
tempold var byte
test var byte
temp = 0

main:

if tempold = temp then
goto main
endif

debug [dec temp]
tempold = temp

goto main

move:

disable extint ’ disable so can ead in byte
pauseus 105 ’ wait for byte to be recieved when baudrate is 9600
temp = RCREG ’ read in byte
enable extint ’ set interrupt again so when next byte comes in it will catch it

resume

Basically how this code works is that it uses external interrupt instead of using the RCINT (which I have basically have given up since this does the task efficiently ). So it detects either the first zero bit or the stop bit (if the data sent is all binary 1s) and then executes the interrupt. In the interrupt we disable it first so that it will not detect the next transition from high to low. First I wait for about 0.1 ms so that the complete byte is received in the RCREG register and then I store the byte into a variable. It exits the interrupt handler to the original code it was in. In the code, it first checks if the byte it just received is the same as the one previously received. If not then it displays it on the debug menu and stores or updates it so that next time we check we will not need to display it again. Basically, it will only display when a new byte is received.

For this code to work however, the UART input MUST be set to 9600 baud and also NEEDS to be connected to pin 15. The bytes I send are equivalent to the decimal value of 99, 100 and 101, which is continuously sent. This is also seen on the debug window. If however someone knows how to do this using the receive interrupt, I will gladly accept your input on the matter.

Sethserial is for use with the hserial subsystem which you are not use. Trying to use it as you are is not going to work. Period. Do not pass Go. Do not collect $200 dollars. You must setup the usart hardware yourself if you want to use the usart interrupts yourself.

acidtech · March 6, 2008, 2:05am

KB:

'Begin

OnInterrupt extINT, move ’ interrupt triggers from level change (high to low or low to
’ high))
setextint ext_h2l
enable extINT ’ When first bit that is a zero or stop bit is recieved from UART, it
’ enables interrupt
sethserial H9600

temp var byte
tempold var byte
test var byte
temp = 0

main:

if tempold = temp then
goto main
endif

debug [dec temp]
tempold = temp

goto main

move:

disable extint ’ disable so can ead in byte
pauseus 105 ’ wait for byte to be recieved when baudrate is 9600
temp = RCREG ’ read in byte
enable extint ’ set interrupt again so when next byte comes in it will catch it

resume

Basically how this code works is that it uses external interrupt instead of using the RCINT (which I have basically have given up since this does the task efficiently ). So it detects either the first zero bit or the stop bit (if the data sent is all binary 1s) and then executes the interrupt. In the interrupt we disable it first so that it will not detect the next transition from high to low. First I wait for about 0.1 ms so that the complete byte is received in the RCREG register and then I store the byte into a variable. It exits the interrupt handler to the original code it was in. In the code, it first checks if the byte it just received is the same as the one previously received. If not then it displays it on the debug menu and stores or updates it so that next time we check we will not need to display it again. Basically, it will only display when a new byte is received.

For this code to work however, the UART input MUST be set to 9600 baud and also NEEDS to be connected to pin 15. The bytes I send are equivalent to the decimal value of 99, 100 and 101, which is continuously sent. This is also seen on the debug window. If however someone knows how to do this using the receive interrupt, I will gladly accept your input on the matter.

Sethserial is for use with the HSerial subsystem which you are not using. Trying to use it as you are is unlikely to work correctly. No further support will be given for SetHserial execpt when using the HSerial system.

You must setup the usart hardware yourself if you want to use the usart interrupts directly with your own code.

When you have a changed your program to setup the appropriate registers please get back to me and I’ll be happy to help you from there. As I’ve stated in other replys you will need to read the usart section(at a bear minimum) of the appropriate PICmicro datasheet to determine what registers must be setup to use the receive function of the usart.