Hi
I made the following c-code:
// Initialize Module 0 in capture mode
CCAPM0=0x21; // Capture positive edge first
// for measuring pulse width
flag_0=0;
n=1;
AUXR1=0x01;
meas_end=res_dph_addr[n];
_asm
mov dph, _meas_end
mov dpl, #0
_endasm;
AUXR1=0;
meas_end=res_dph_addr[n+1];
and in the assembler code it looks like this:
mov _CCAPM0,#0x21
; measure_pulses_03.c:116: flag_0=0;
clr _flag_0
; measure_pulses_03.c:118: AUXR1=0x01;
mov _AUXR1,#0x01
; measure_pulses_03.c:119: meas_end=res_dph_addr[n];
; measure_pulses_03.c:123: _endasm;
mov dph, #_meas_end
mov dpl, #0
; measure_pulses_03.c:124: AUXR1=0;
mov _AUXR1,#0x00
; measure_pulses_03.c:125: meas_end=res_dph_addr[n+1];
mov dptr,#(_res_dph_addr + 0x0002)
clr a
movc a,@a+dptr
mov _meas_end,a
The variable meas_end is not set until after the _asm block but I need it
before the block. The obvious solution is to set DPL and DPH in C :)
But I might need to do use inline assembler some other time and I don't want
my variables to be optimised away.
Can anyone explain this behaviour?
The other question
I have spent the last two days on making a function that enables interrupts
from PCA to make measurements. It should then wait for a keyboard input to
finish the measurement.
EC = 1;
EA = 1; // Enable global interrupt
CR = 1;
ggetchar();
CR = 0; // Turn PCA timer off
IE = 0x0; // Disable all interrupt
where the functions are defined below. The problem is that the program always
jumps over the ggetchar() function without waiting and even if I only put a
while(1) statement instead of the ggetchar() function.
I guess this means tedious debugging but if it is some simple misunderstanding
I would be very happy :)
unsigned char ggetchar()
{
while(P2==0xFF);
usleep(30000);
return P2;
}
void usleep(unsigned int j)
{
unsigned int i;
for ( i=0;i<=j;i++);
}
Thanks
Gudjon
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