PIC Analog Tutorial

[aljamri]

I'm doing Analog Tutorial from Nigel's. (Tutorial # 11), replaced 16f876 with 16f876a. LCD not seemed initialized, regardless hardware double check the following findings still exist:

• LCD not initialized ( top line blocks only )
• If +5 volts connection to MCLR ( pin #1 ) moved two, three times, LCD initialized,
• When LCD initialized, it may show two lines or one line sometimes.
• If the LCD shows two lines, it removes the first an second characters from Tutorial ( appears torial )

Note: I could not find 12 Pico Capacitors for Main Board 2, I put 6 Picos.

Is there any thing wrong in all of these.

Thanks

 

[Nigel Goodwin]

I'm doing Analog Tutorial from Nigel's. (Tutorial # 11), replaced 16f876 with 16f876a. LCD not seemed initialized, regardless hardware double check the following findings still exist:

• LCD not initialized ( top line blocks only )
• If +5 volts connection to MCLR ( pin #1 ) moved two, three times, LCD initialized,
• When LCD initialized, it may show two lines or one line sometimes.
• If the LCD shows two lines, it removes the first an second characters from Tutorial ( appears torial )

Note: I could not find 12 Pico Capacitors for Main Board 2, I put 6 Picos.

Is there any thing wrong in all of these.

Thanks

Have you altered the config word?.

Try 0x2909 for the 876A.

 

[aljamri]

Yes Nigel I replaced it with It's 0x290A as per your previous recomendation, or it is It's 0x2909 ?

i'll try both tommorow and let you know.

thanks.

 

[Nigel Goodwin]

Yes Nigel I replaced it with It's 0x290A as per your previous recomendation, or it is It's 0x2909 ?

Sorry, my mistake, 0x209A for HS and 0x2909 for XT, with 20MHz you should use HS, although XT may well work anyway.

 

[aljamri]

And what about 6 Pico instead of 12, is it ok ?


by the way i've repeated all LED tutorial using 16f876.a and they work, then i've repated LCD tutorials and they worked well except for the first or/and second characters are missing from both lines.

Thanks

 

[Nigel Goodwin]

And what about 6 Pico instead of 12, is it ok ?


by the way i've repeated all LED tutorial using 16f876.a and they work, then i've repated LCD tutorials and they worked well except for the first or/and second characters are missing from both lines.

Thanks

As long as it's oscillating the capacitor values make little difference.

Try increasing the delays a little, your LCD may require more time?.

 

[aljamri]

Still no result, I tried LCD Tutorial, and everything is ok expect the first character in top line was not shown.

I replaced

		movlw	0x07
		movwf	CMCON		;turn comparators off (make it like a 16F84)

with this

		BANKSEL ADCON1		;disable A2D
    		movlw   0x06
    		movwf   ADCON1
    		BANKSEL PORTA

As recommended in tutorials, is that ok even I'm doing Analog input.

I'll try playing with Delay and let you know

Thanks

 

[Nigel Goodwin]

As recommended in tutorials, is that ok even I'm doing Analog input.

As long as you turn them back on if you need them - I generally use that code to turn them off regardless, because then you don't forget!

 

[Pommie]

		BANKSEL ADCON1		;disable A2D
    		movlw   0x06
    		movwf   ADCON1
    		BANKSEL PORTA

As recommended in tutorials, is that ok even I'm doing Analog input.

Putting 6 in ADCON1 will make all inputs digital. You need to refer to section 11 of the data sheet to work out the value required in ADCON1. You don't state which analogue input you are using so I cannot advise a value.

BTW, the default value for CMCON is 7 and so the comparators are switched off anyway.

Mike.

 

[Nigel Goodwin]

BTW, the default value for CMCON is 7 and so the comparators are switched off anyway.

The CMCON line was from a 16F628 example, where they are ON by default.