Bootloader please help

[AlanUK]

Using 16F877 device- 4Mhz clock - programmed 16F877 with hex file from microchip website. 16F877 4MHZ 19200 Baud. Using CCS PCM ver 2.707 tryed both extra lines in code

#org 0x1F00, 0x1FFF{} ,#org 0x1F00, 0x1FFF void loader16F877(void){}

Problems :-

Downloads ok if I switch +5V off then on and seems to run code - only checked with simple code tho. Using downloader 1.08

Doesnt download if I reset

Doesnt run program if I just power on circuit as normal - you have got to use bootloader to run code, i.e power off then on.

Known hardware working.

Any ideas please ?

Alan

[PCM programmer]

Check the config bit settings before you program the HEX file into
your 16F877. The HEX file from Microchipc has certain default config
bit settings that are not perfect.

If you're using PicStart-Plus with MPLAB as a programmer, then there
is a little window that pops up that will let you change the config bits.

I suggest using these settings:

Oscillator: XT
Watchdog: OFF
Power-up Timer: On
Code Protect: OFF
Brownout Detect: On
Low Voltage Program: Disabled
Data EE Protect: OFF
Flash Program Write: Enabled
Background Debug: Disabled

[AlanUK]

Thanks for the reply m8 - yeah using Picstart plus and the config bits were causing the problem - just changed the low voltage programming part and it runs.

Thanks

Alan