NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/robotics/2889

Text File | 1993-01-12 | 2.6 KB | 78 lines

Newsgroups: comp.robotics
Path: sparky!uunet!paladin.american.edu!howland.reston.ans.net!spool.mu.edu!agate!iat.holonet.net!bsmall
From: [e-mail] (Brad Smallridge)
Subject: PICs
Message-ID: <[e-mail]>
Organization: HoloNet National Internet Access BBS: 510-704-1058/modem
Date: Tue, 12 Jan 1993 22:13:45 GMT
Lines: 68

PIC UPDATE

Last month I wrote an article on PICs, Programmable Integrated
Circuits, and placed the article in several robot newsletters
and also on USENET, an electronic news service. The response,
especially from USENET, has been useful.

First of all, we can forget about the Motorola 68L705. I
was told that after the current supply of parts is depleted,
the 68L705 will no longer be available.  On the other hand,
Microchip is strengthening its PIC line with an advancement
over the PIC16C5x series called the PIC16C71 including these
new additions:

 * Four 8-bit A/D Inputs
 * Four Interrupt Sources
 * Eight Level Hardware Stack
 * Programmable On-board Pull-up Resistors

The addition of Analog to Digital Converter Inputs makes
the chip much more attractive. I can imagine several more
applications using the analog capabilities. Too bad there is
no Digital to Analog Converter. The external Interrupt
allows an outside occurrence to trigger an action by the PIC
as well as an internal timer Interrupt capability. The stack
is eight deep getting rid of an annoying limitation on the
16C5x series that are only two deep. And the programmable
Pull-up simplyallows you to use fewer components in your
design -- a nice touch.

Microchip also expanded the internal instruction word from
12 bits to 14 bits. This cleaned up the instruction set. For
example, the Jump instruction can go anywhere in the 1K
program memory without regard to what page it's on. Also the
registers are all addressable without selecting register
banks. These improvements create cleaner and faster code.

The new PIC requires a programmer upgrade from Parallax
which cost $99 and is available now. My costs now are up to
about $350 total. There are no Parallax ICE or emulators
available yet. The PIC16C71 chips themselves are hard to get
and right now and are only available on a sample basis. I
suggest you call Microchip and get information on the office
nearest you.

Microchip Technology [phone]
Microchip (Sunnyvalle Office)[phone]
Trinity Technologies (Sunnyvalle) [phone]
Parallax,Inc [phone]

Brad Smallridge
Phone [phone]
FAX [phone]
BBS [phone]
EMAIL [e-mail]