You set the TRIS bits for 0's for the port pins you want to write to; i.e. setting TrisB to '11110000'B would leave RB7..RB4 as inputs but make RB3..RB0 outputs. The TRIS bits are 'usually' write-only; you usually know how you last left them set.
Microchip does not intend to support the TRIS instruction in future products.
In place of a TRIS command, use a MOVWF TRIS(A,B,etc) assuming that W is loaded with the desired mask. You also need to switch to bank 1 before doing the movwf command, where the tris addresses then match the port addresses. That's why people still like to use the tris command - no bank switch is required. If the tris command exists for a chip, it will always exist for that chip - Microchip cautions against using it in the case of using the same software on a future product that will not have the tris command. In the my16F87x data sheet, they emphatically say DONOT USE the tris instruction. In fact, on the '877, the TRIS command works only on ports a, b, c not d, e
Unused pins@, Input/Output@
I am a begginer in Software field but i can well understand and do coding i believe.i am writing soft ware for 10x8 key matrix for 16F883 controller.I tried to initialise all the port as per how i want to use for my application. but the GPIO values are not updating when i am using the HI-TECH compilor.is there any special sequence of register initialisation which we need to follow strictly to get it done correctly..And is there any site or book from which i can get a sample code in C for my applicationJames Newton of Massmind replies: Certainly HI-TECH must provide some code samples that setup GPIO?+
|file: /Techref/microchip/tris.htm, 3KB, , updated: 2012/9/24 16:28, local time: 2017/12/18 04:56,
|©2017 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://www.piclist.com/techref/microchip/tris.htm"> TRIS</A>
|Did you find what you needed?|
PICList 2017 contributors:
o List host: MIT, Site host massmind.org, Top posters @20171218 RussellMc, Van Horn, David, Sean Breheny, James Cameron, alan.b.pearce, IVP, Neil, Bob Blick, David C Brown, John Gardner,
* Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.
Welcome to www.piclist.com!