Hi all,
I am trying to setup a RF connection between a PC and a PIC using the MaxStream ZigBee modules. If i send a single byte from the PC to the PIC everything is ok but how do I send more then one?
I am using hardware interrupts for the USART and the USART itself only has a 1 byte buffer.
I need a way to capture 10 bytes with the PIC into a buffer array and then process it afterwards.
HSERIN uses the hardware UART, but uses it in a way that's more like the bit-banged method of SERIN. Use the STR modifier to get 10 bytes into an array.Quote:
Originally Posted by PJALM
Thanks for the advise but at the time of interrupt there is only one byte to get because the buffer is only one byte in size.
I need a way to capture the data one byte at a time and put each byte into the array as it arrives. This means I need to track which byte I am on and know when to start capturing and when to stop.
I will put up some sample code I made to give you an idea of what I am trying to achieve.
Ok here is a snippet from the code i am working on.
Maybe this will trigger some ideas.
Code:
DEFINE OSC 48
DEFINE LOADER_USED 1
DEFINE RESET_ORG 800h ' For Microchip USB Bootloader
DEFINE INTERRUPT_ORG 808h ' For Microchip USB Bootloader
'-------------------------------------------------------------------------------
' System Settings
'-------------------------------------------------------------------------------
ADCON1 = 15 ' Set all I/Os to Digital
INTCON2.7 = 1 ' Disable PortB Pullups
CMCON = 7 ' Disable Comparators
My_Address VAR BYTE
i VAR BYTE
ii VAR WORD
i = 0
ii = 0
My_Address = 0
'-------------------------------------------------------------------------------
'-------------------------------------------------------------------------------
' RF Settings
'-------------------------------------------------------------------------------
DEFINE HSER_BAUD 9600
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 20h
'DEFINE HSER_SPBRG 25
DEFINE HSER_CLROERR 1
RF_ACK CON $01 ' Expected acknowledge char from RS-485
RF_STX CON $02 ' Start of Transmission Byte
RF_ETX CON $03 ' End of Transmission Byte
RF_POS CON $04
RF_To_Address VAR BYTE
RF_From_Address VAR BYTE
RF_Command VAR BYTE
RF_Parameter VAR WORD
RF_Data VAR BYTE
RF_Buffer VAR BYTE[7]
RF_Bytes_Sent VAR BYTE
RF_Bytes_Received VAR BYTE
RF_Sending_Data VAR BIT
RF_Receiving_Data VAR BIT
RF_Send VAR BIT
RF_ACK_Received VAR BIT
RF_PPP_Received VAR BIT
RF_POS_Received VAR BIT
RF_B0 VAR BYTE
RF_B1 VAR BYTE
RF_To_Address = 0
RF_From_Address = 0
RF_Command = 0
RF_Parameter = 0
RF_Send = 0
RF_Bytes_Received = 0
RF_Receiving_Data = 0
RF_ACK_Received = 0
RF_PPP_Received = 0
RF_POS_Received = 0
RF_B0 = 0
RF_B1 = 0
'-------------------------------------------------------------------------------
'-------------------------------------------------------------------------------
' Interrupt Settings
'-------------------------------------------------------------------------------
INTCON.6 = 1 ' Enable Peripheral Interrupts
INTCON.7 = 1 ' Enable Global Interrupt Handler
PIE1.4 = 0 ' Disable USART Transmit Interrupt
PIE1.5 = 1 ' Enable USART Receive Interrupt
'-------------------------------------------------------------------------------
PAUSE 500
My_Address = 18
ON INTERRUPT GOTO Main_Interrupt_Handler
ENABLE INTERRUPT
'-------------------------------------------------------------------------------
' Main Program Loop
'-------------------------------------------------------------------------------
MainLoop:
GOSUB Get_My_Address
'IF RF_Receiving_Data = 0 THEN
' IF RF_Command != 0 THEN
' IF RF_To_Address = My_Address THEN
' GOSUB RF_Process_Command
' ENDIF
' ENDIF
'ENDIF
PAUSE 50
GOTO MainLoop
'-------------------------------------------------------------------------------
'-------------------------------------------------------------------------------
' Send RF data
'-------------------------------------------------------------------------------
RF_Send_Data:
RF_From_Address = My_Address
RF_Ack_Received = 0
RF_PPP_Received = 0
RF_Buffer(1) = RF_STX 'Start
RF_Buffer(2) = RF_To_Address + 4 'To Address
RF_Buffer(3) = RF_Command 'Command
RF_Buffer(4) = RF_Parameter.HighByte + 4 'Parameter High Byte
RF_Buffer(5) = RF_Parameter.lowbyte + 4 'Parameter Low Byte
RF_Buffer(6) = RF_From_Address + 4 'From Address
RF_Buffer(7) = RF_ETX 'End
FOR i = 1 TO 25
PAUSE 10
NEXT
FOR i = 1 to 7
RF_Data = RF_Buffer(i)
HSEROUT [RF_Data] 'Send the Data Byte
PAUSE 25
NEXT
FOR i = 1 TO 25
PAUSE 10
NEXT
FOR i = 1 TO 7
RF_Buffer(i) = 0
NEXT
RF_To_Address = 0
RF_From_Address = 0
RF_Command = 0
RF_Parameter = 0
RETURN
'-------------------------------------------------------------------------------
'-------------------------------------------------------------------------------
' Interrupt Handler
'-------------------------------------------------------------------------------
DISABLE INTERRUPT ' No interrupts past this point
Main_Interrupt_Handler:
'---------------------------------------------------------------------------
' USART Receive Interrupt
'---------------------------------------------------------------------------
IF PIR1.5 = 1 THEN
PAUSE 50
HSERIN [RF_B0]
SELECT CASE RF_B0
CASE RF_STX
RF_Bytes_Received = 1
RF_Receiving_Data = 1
RF_Bytes_Received = 0
FOR i = 2 TO 7
RF_Buffer[i] = 0
NEXT
RF_Bytes_Received = RF_Bytes_Received + 1
RF_Buffer(RF_Bytes_Received) = RF_B0
CASE RF_ETX
RF_Bytes_Received = RS485_Bytes_Received + 1
RF_Buffer(RF_Bytes_Received) = RF_B0
RF_Receiving_Data = 0
RF_To_Address = RF_Buffer(2) - 4
RF_Command = RF_Buffer(3) - 4
RF_Parameter.HighByte = RF_Buffer(4) - 4
RF_Parameter.LowByte = RF_Buffer(5) - 4
RF_From_Address = RF_Buffer(6) - 4
CASE ELSE
IF RF_Receiving_Data = 1 THEN
RF_Bytes_Received = RF_Bytes_Received + 1
RF_Buffer(RF_Bytes_Received) = RF_B0
ENDIF
END SELECT
PIR1.5 = 0
ENDIF
'---------------------------------------------------------------------------
'---------------------------------------------------------------------------
' USB Interrupt
'---------------------------------------------------------------------------
IF PIR2.5 = 1 THEN
DEBUG 13, 10, "[ INTERRUPT ] USB Interrupt", 13, 10
PIR2.5 = 0
ENDIF
'---------------------------------------------------------------------------
IntDone:
RESUME ' Return to main program
ENABLE INTERRUPT
'-------------------------------------------------------------------------------
END
Has anyone had any luck with this code yet or hav any sugestions?
Has anyone at all had any experience with this? I still cannot successfully receive more then 1 byte without problems. ANy help at all would be greatly apreciated.
Thanks
When using ON INTERRUPT the interrupts don't get handled until the currently executing PBP statement has finished.
At 9600 baud it only takes 1.04ms per byte. With the USARTS 2 byte buffer, the longest that any statement can take is 2.08ms. Anything taking longer will cause the buffer to overflow. Then with [DEFINE HSER_CLROERR 1] the program never even knows it lost data.
With PAUSE 50 in the MainLoop, you could easily loose 15-20 bytes at a time.
If you were using ASM interrupts, that wouldn't be a problem.
HTH,