How to use the internal oscillator of 16f628a?

[apocrypha]

I used to program with 16f84a but the memory was not enough so I switched to 16f628a. In 84a, I used portb to drive a 4-bit LCD and porta as input.

How can I use the internal oscillator of 628a? How shall I initalize porta if i use RA6 and RA7 for xt oscillator, trisa=%00111111 or %11111111? or how does the chip read the RA6&7 pins when used for xt, 0 or 1? Also, what changes in the program should I consider? I use mikrobasic..help!

 

[Henrico]

porta of 16f628a

I used to program with 16f84a but the memory was not enough so I switched to 16f628a. In 84a, I used portb to drive a 4-bit LCD and porta as input.

How can I use the internal oscillator of 628a? How shall I initalize porta if i use RA6 and RA7 for xt oscillator, trisa=%00111111 or %11111111? or how does the chip read the RA6&7 pins when used for xt, 0 or 1? Also, what changes in the program should I consider? I use mikrobasic..help!

Try www.winpicprog.co.uk there are loads of tutorials on the 16F628 perhaps you will find your answers there.

Good Luck

 

[glenjoy]

16f628a porta portb mikrobasic

Configuration bits are mostly done during the programming of the microcontrollers.

Read the PIC16F628A, it can give more details.

 

[mit]

16f628a configuration bits

You can used RA7+RA6 as XT osc and used RB2 and RB3 substitute. And change a little bit of your code like:
MOVLW B'00000011'
MOVWF TRISB
BANKSEL PORTB
But for PIC PORT A you can select which one output or input depend on bit selection such as
MOVLW B'11110000'
MOVWF TRISA
that mean RA7, RA6, RA4 as input, RA3-RA0 as output

Good luck!

 

[glenjoy]

help with 16f628a configuration?

You can used RA7+RA6 as XT osc and used RB2 and RB3 substitute. And change a little bit of your code like:
MOVLW B'00000011'
MOVWF TRISB
BANKSEL PORTB
But for PIC PORT A you can select which one output or input depend on bit selection such as
MOVLW B'11110000'
MOVWF TRISA
that mean RA7, RA6, RA4 as input, RA3-RA0 as output

Good luck!

Using the XT pins as an I/O requires configuring the CONFIGURATION WORD and not just by setting the equivalent TRIS registers.

Read your PIC16F628A datasheet.