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arulgobi
Joined: 03 Sep 2006
Posts: 3
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 Posted: Sun Sep 03, 2006 4:23 am Post subject: 16f84a help. |
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hi,
i am new to this Pic programming, i have to do a project. For that we are using PIC Millennium Board . we want to handle keypad 4*4(8 pins) . LCD (min 6 pins) and we want to handle two LED. So almost 16pins . but in the 16f84a we have only 13 pins. Can we handle this situation? Please help me.
thankyou,
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KC
Joined: 05 May 2006
Posts: 99
Location: Victoria BC Canada
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| Posted: Thu Sep 14, 2006 2:04 am Post subject: |
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| Quote: | | Can we handle this situation |
You'll need some external chips such as a data latch or shift register to expand your IO lines. Or use a different PIC with more IO. I personally would use a PIC like the 16F873 which has enough IO for the job and dump the 16F84 for this project.
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arulgobi
Joined: 03 Sep 2006
Posts: 3
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| Posted: Tue Sep 19, 2006 8:14 am Post subject: |
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Hi,
Thanks for your reply.This is actually for a education purpose. so they prefer midrange PIC.
I some or how solve that problem. Through using upper RB4-RB7 for both keypad and LCD data pins. It is working fine in the Simulator (proteus) but when I run in the development board, LCD is doing some thing else mean displaying the message and randomly printing some unwanted character.
Is there any reason for that ?
Thanks for advance
Arulgobi. |
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KC
Joined: 05 May 2006
Posts: 99
Location: Victoria BC Canada
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| Posted: Wed Sep 20, 2006 1:12 am Post subject: |
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| Quote: | | Is there any reason for that ? |
I would need to see a diagram of your circuit, but I would guess that you need to disable the LCD modual when you do the Keypad scan routine.
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arulgobi
Joined: 03 Sep 2006
Posts: 3
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| Posted: Wed Sep 20, 2006 7:03 am Post subject: |
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But if there is any coding error it has effects the simulator also but it is working properly.
RA0 - ENABLE
RA1 - RS
R/W ground
RB0 - take input form keypad
RB1 - take input form keypad
RB2 - take input form keypad
RB3 - take input form keypad
RB4 -Send out to keypad and send data to LCD
RB5-Send out to keypad and send data to LCD
RB6-Send out to keypad and send data to LCD
RB7-Send out to keypad and send data to LCD
But I am controlling the LCD through the PORTA. So I think there keypad can’t effect the LCD.
how i can send the image?
Thanks a lot,
arulgobi |
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