PCH - IO Problem

[Jerry Finsen]

I have a series of programs that worked fine on a 16F877 that I am porting to an 18F458. My Keyboard routines that work fine on the 877 do not work on the 458. I have been able to strip the code to the minimum amount that demonstrates the problem.

I suspect I am missing something simple --- like a fuse or something. Spent two days on this --- time to look for help.

I am running 3.148 of the compiler on a Win2k machine. Target board is the Micro Engineering X1 Board.

//****************************************************************************************

#ifdef __PCH__
#include <18F458.h>
#fuses HS,NOWDT,WDT1,NOLVP
#else
#include <16f877.h>
#fuses HS,NOWDT,NOLVP
#endif

#use delay(clock=20000000)

#use rs232(baud=9600, parity=n, xmit=PIN_C6, rcv=PIN_C7, bits=8)
#use FAST_IO(B)

void KbdInit(void);
unsigned ReadKeyboard(int1 Hold);

void main() {

unsigned Key;

setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_CLOCK_DIV_2);
setup_psp(PSP_DISABLED);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_INTERNAL|T1_DIV_BY_8);
setup_timer_2(T2_DISABLED,0,1);

#ifdef __PCH__
setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
setup_comparator(FALSE);
setup_wdt(WDT_OFF);
#endif

KbdInit();
while(1){
Key = ReadKeyboard(1);
if (Key>0)
printf("\n\r KeyPress = \%d", Key);
}
}
//************************************************
void KbdInit(void)
{
port_b_pullups(TRUE);
}
//************************************************
unsigned ReadKeyboard(int1 Hold)
{
unsigned Mask, Col, Row, Key;

/* See if any keys are pressed */
SET_TRIS_B(0);
OUTPUT_B(0);
SET_TRIS_B(0xF0);

Key = INPUT_B();
if (Key == 0xF0)
return(0);

/* When no Key is pressed, "Key" contains:
0x00 on the 18F458 and
0xF0 on the 16F877
0xF0 is the desired response
*/
printf("\n\n\rKey Press \%2X", Key);

//* Code Snipped

return(0);
}
___________________________
This message was ported from CCS's old forum
Original Post ID: 12894

[Neutone]

:=
:=I have a series of programs that worked fine on a 16F877 that I am porting to an 18F458. My Keyboard routines that work fine on the 877 do not work on the 458. I have been able to strip the code to the minimum amount that demonstrates the problem.
:=
:=I suspect I am missing something simple --- like a fuse or something. Spent two days on this --- time to look for help.
:=
:=I am running 3.148 of the compiler on a Win2k machine. Target board is the Micro Engineering X1 Board.
:=
:=//****************************************************************************************
:=
:=#ifdef __PCH__
:= #include <18F458.h>
:= #fuses HS,NOWDT,WDT1,NOLVP
:=#else
:= #include <16f877.h>
:= #fuses HS,NOWDT,NOLVP
:=#endif
:=
:=#use delay(clock=20000000)
:=
:=#use rs232(baud=9600, parity=n, xmit=PIN_C6, rcv=PIN_C7, bits=8)
:=#use FAST_IO(B)
:=
:=void KbdInit(void);
:=unsigned ReadKeyboard(int1 Hold);
:=
:=void main() {
:=
:=unsigned Key;
:=
:= setup_adc_ports(NO_ANALOGS);
:= setup_adc(ADC_CLOCK_DIV_2);
:= setup_psp(PSP_DISABLED);
:= setup_spi(FALSE);
:= setup_timer_0(RTCC_INTERNAL);
:= setup_timer_1(T1_INTERNAL|T1_DIV_BY_8);
:= setup_timer_2(T2_DISABLED,0,1);
:=
:= #ifdef __PCH__
:= setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
:= setup_comparator(FALSE);
:= setup_wdt(WDT_OFF);
:= #endif
:=
:= KbdInit();
:= while(1){
:= Key = ReadKeyboard(1);
:= if (Key>0)
:= printf("\n\r KeyPress = \%d", Key);
:= }
:=}
:=//************************************************
:=void KbdInit(void)
:={
:= port_b_pullups(TRUE);
:=}
:=//************************************************
:=unsigned ReadKeyboard(int1 Hold)
:={
:= unsigned Mask, Col, Row, Key;
:=
:= /* See if any keys are pressed */
:= SET_TRIS_B(0);
:= OUTPUT_B(0);
:= SET_TRIS_B(0xF0);
:=
:= Key = INPUT_B();
:= if (Key == 0xF0)
:= return(0);
:=
:=/* When no Key is pressed, "Key" contains:
:= 0x00 on the 18F458 and
:= 0xF0 on the 16F877
:= 0xF0 is the desired response
:=*/
:=printf("\n\n\rKey Press \%2X", Key);
:=
:=//* Code Snipped
:=
:= return(0);


It may be as simple as using a delay to allow the port to change directions before reading it. It takes a noticable time for it to switch directions.

SET_TRIS_B(0xF0);
delay_cycles(2);
Key = INPUT_B();


:=}
___________________________
This message was ported from CCS's old forum
Original Post ID: 12900

[Jerry Finsen]

It was that simple! Thanks. Now to find where in the Data Sheet that little bit of information is found! It must be in there somewhere.

Thanks again

jerry

:=It may be as simple as using a delay to allow the port to change directions before reading it. It takes a noticable time for it to switch directions.
:=
:=SET_TRIS_B(0xF0);
:=delay_cycles(2);
:=Key = INPUT_B();
:=
:=
:=:=}
___________________________
This message was ported from CCS's old forum
Original Post ID: 12901