blink a single led

[MINHLE]

hi,
can any friend help this situation
the program had run well for some years, now this fail even if to blink a single led on a breadboard.
i have tried several chips: 16f 676, 876,,877a, 18f2455, 26k20... all the same bad result?
the programmer is just updated to 5.1 last night
thank for your help

i post a program here (pic18f26k20):
-------------------------------------------------------

INCLUDE "h:\AllDigital.pbp"
ASM
__CONFIG _CONFIG1H, _FOSC_INTIO67_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
__CONFIG _CONFIG2H, _WDTEN_ON_2H & _WDTPS_512_2H
__CONFIG _CONFIG3H, _CCP2MX_PORTC_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _HFOFST_ON_3H & _MCLRE_ON_3H
__CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L
ENDASM
OSCCON = $70 Internal oscillator is set to 16MHz $62 ' 8mhz--- '; Primary Clock is selected as system clock.
OSCTUNE = $40 'HFINTOSC selected; PLL enabled; Factory calibrated frequency
define osc 64
ADCON0 = 0
CM1CON0.7 = 0
CM2CON0.7 = 0
portb = 0
latb = 0
trisb = 0
'------------------------------------------

program:
portb = $ff
pause 1000
portb = 0
pause 1000
GOTO program
'==============================================

end

[Demon]

Upper case defines.

[MINHLE]

tks for your rePLY,
it is not the problem of program, nor breadboard? nor programmer?- it is suddenly dead
note that is well simulated in the proteus sofware

[Demon]

If it is suddenly dead, I'd pay close attention to the breadboard connections and power supply.

You should also read up on READ MODIFY WRITE.
http://www.picbasic.co.uk/forum/show...d+modify+write

[MINHLE]

TKS for ur reply,
no way. power supply and every thing is ok
the chip was programmed a month ago is ok (on the bread board and on the circuit), just after last month, every thing is corrupted ( even on the sam breadboard connection or the same pcb)
i reprogram mplab and pbp but no help

[towlerg]

What has changed on the PC and programmer? In post#1 you said "programmer is just updated to 5.1 last night". if you mean that you updated the firmware in the programmer, then try reverting to the previous version.

BTW RMW hardly an issue with 1 sec between writes.