Serial Output Routines

Serial Output Routines (without using the USART)

It is nice for debugging purposes to use a general I/O pin for displaying debugging data to a PC, rather than using the USART pin, which may be tied up for other purposes. The routines described here let the used define the port, pin, baud rate, and polarity (true or inverted) of the output.

The following #DEFINE statements are needed in your main() routine:

#define DEBUG_REG PORTB 
    The port to use for the serial output

#define DEBUG_BIT 7
    The bit to use for serial output 

#define DEBUG_POLARITY TRUE|INVERTED 
    default is TRUE: direct to RS232
          Inverted means via a MAX232 or equivalent 

#define DEBUG_TRIS TRISB
    If this is defined, the pin will be set to output in the routine, and then restored to its original value on exit. 

The baud rate is set by either a #DEFINE if you want to use the pauseus routine, or by a Const statement if you want to use the delayus routines. The formula is 
        DEBUG_DELAY  = (1000000 / (baud rate)) - (52 / Osc freq in mHz). 

const DEBUG_DELAY = 102    ' To use the Basic18 delayus() routine
#define DEBUG_DELAY 102    ' To use the pauseus() routine 

Click on a routine name to see the code

debugc(character)
        send character (a single byte) 

debugs(string)
        send the character string in string

debugnl() or debugCRLF()
        send a new line (return plus line feed) 

DumpMem(addr(var), len, string)
        Puts the contents of RAM, in hex, formatted as groups of 4 bytes (8 hex characters) into a string. Useful for debugging. 

Parameters:

var       - the RAM variable where the dump will start
len       - the length, in bytes, of RAM to dump
string   - a string into which the data will be placed. It must twice as large as len 

Example:

dim x as single
dim s(12) as string
DumpMem(addr(x),4,s)