68300

Hello All
Happy New Year to everybody.

Due to a shortage of bit output pins on our board I have tried using one of
the Dual function Port E pins ( either bus control pins or bit port pins) as
an bit output with conspicuous lack of success.
I wonder if this is a problem unique to me or not.

On page D19 of the User Manual the dual use of Port E is described. I have
used PEPA3 as a bit output (externally pulled high by a resistor) instead of
it driving the RMC bus control pin as we do not use this pin in the design.
I dropped into assembler as you can see. All is well initialising the port
as below:

// Set up PORT E, one bit of this controls the pSOS+ Interrupt Clock Source
 PEPAR = PEPAR_SET ;  // Select the RMC pin only as a port, rest Bus Control
// Set the RMC / PE3 pin as a output, rest unchanged
 asm(" bset #3,$00FFFA15") ;

However if I execute the next line the board crashes. It appears as if the
memory "disappears".
If I comment out the line below than the code runs on correctly.

// Set PE2 low, this enables the pip IRQ clock source. Pips will be coming
now.
    asm(" bclr #3,$00FFFA11") ;

Am I missing something here?
-
Robert Manktelow
Telspec Europe Ltd, Rochester, ME1 3QU
Phone +44 (0)1634 687 133 extension 2346