What mean : tris PORTA - Electronic Circuits Projects Diagrams Free

savnik · 15th February 2007, 05:47 AM

I have the below code:

---------------------------------------------------
trisabuf VAR BYTE
movlw 0x10 ; 00010000 - RA4 is entry
movwf trisabuf
---------------------------------------------------
bsf trisabuf,3
movf trisabuf,W
tris PORTA
----------------------------------------------------

What mean : tris PORTA ;
This mean that PORTA = trisabuf ;

Papabravo · 15th February 2007, 06:23 AM

On older versions of the PIC architecture there was a specific instruction that loaded the the TRIS register. On the newer versions you use a move instruction just like every other file register. If you read the datasheets really carefully they discourage the use of the dedicated instruction in favor of the more generic move instruction

savnik · 15th February 2007, 06:24 AM

Quote:

Originally Posted by Papabravo

On older versions of the PIC architecture there was a specific instruction that loaded the the TRIS register. On the newr versions you use a move instruction just like every other file register. If you read the datasheets really carefully they discourage the use of the dedicated instruction in favor of the more generic move instruction

Yes is for PIC16C54

Gayan Soyza · 15th February 2007, 11:23 AM

Quote:

bsf trisabuf,3
movf trisabuf,W
tris PORTA

Simply You can use this line to turn on RA3 on PORTA

Code:

BSF	PORTA,3

Papabravo · 15th February 2007, 10:48 PM

Quote:

Originally Posted by savnik

Yes is for PIC16C54

On such an old device there is no alternative to the TRIS instruction because that register does not have a valid register file address.

savnik · 16th February 2007, 06:14 AM

I found:

bcf _trisabuf,3
bsf STATUS, RP0
movf _trisabuf,W
movwf TRISA
bcf STATUS, RP0

I use for pic16f628a

**Nigel Goodwin** · 16th February 2007, 07:45 AM

Quote:

Originally Posted by savnik

I found:

bcf _trisabuf,3
bsf STATUS, RP0
movf _trisabuf,W
movwf TRISA
bcf STATUS, RP0

I use for pic16f628a

Is there some reason for using '_trisabuf'?, instead of just

Code:

	   bsf	 STATUS, RP0     
	   bcf   TRISA, 3            
	   bcf	 STATUS, RP0

savnik · 16th February 2007, 05:58 PM

You are right
Thank you

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15th February 2007, 05:47 AM	(permalink)
savnik	What mean : tris PORTA I have the below code: --------------------------------------------------- trisabuf VAR BYTE movlw 0x10 ; 00010000 - RA4 is entry movwf trisabuf --------------------------------------------------- bsf trisabuf,3 movf trisabuf,W tris PORTA ---------------------------------------------------- What mean : tris PORTA ; This mean that PORTA = trisabuf ; Last edited by savnik; 15th February 2007 at 06:28 AM.

15th February 2007, 06:23 AM	(permalink)
Papabravo	On older versions of the PIC architecture there was a specific instruction that loaded the the TRIS register. On the newer versions you use a move instruction just like every other file register. If you read the datasheets really carefully they discourage the use of the dedicated instruction in favor of the more generic move instruction Last edited by Papabravo; 15th February 2007 at 10:47 PM.

16th February 2007, 06:14 AM	(permalink)
savnik	I found: bcf _trisabuf,3 bsf STATUS, RP0 movf _trisabuf,W movwf TRISA bcf STATUS, RP0 I use for pic16f628a

16th February 2007, 05:58 PM	(permalink)
savnik	You are right Thank you