PIC not working properly (16F877A)

[vishaletm]

When a wire is connected or i touch the PGM pin of PIC 16F877A it stop working. What may be the cause? Program worked successfully in proteus.

[supra]

Ur pic or LCD is dead
If u touched with finger while power is on.
If u move jumper wire or connect to pin while power is on

Or if u have extra lcd. Then either lcd nor pic is bad

Never leave power supply on, while working on board
HTH,

Btw: i had to buy extra lcd and pic

[Mince-n-Tatties]

in the real world you will need to drive the MCLR (reset) line correctly and it often proves best to ground the spare data pins D0-D3.

lcd_and_reset.jpg (154.13 KiB) Viewed 1888 times

[kahtan]

Hi,
PGM pin is used in LVP (Low-Voltage ICSP Programming).
So you have to disable LVP in the CONFIGURATION word bit 7;

bit 7 LVP: Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit
1 = RB3/PGM pin has PGM function; low-voltage programming enabled
0 = RB3 is digital I/O, HV on MCLR must be used for programming

when you touch it the MCU enter proramming mode if LVP bit = 1.

Datasheet page: 158
To enter Programming mode, VDD must be
applied to the RB3/PGM provided the LVP bit is set.
The LVP bit defaults to on (‘1’) from the factory.

[vishaletm]

Now its OK. Low voltage programming disabled. But now it is not detecting Keypad entry. I tried pull down at all pins, no change. Pleases help i have to submit project on saturday.

[filip]

Hi,

I believe I have answered you here :
http://www.mikroe.com/forum/viewtopic.p ... 92#p183992

Regards,
Filip.