Re: MISC-d Digest V96 #47

[jfox@xxxxxxxx (Jeff Fox)]

Dear MISC Readers:

Jiunn-jye Huang <jjhuang@cm.nctu.edu.tw> asked:

>Hello,
>    I am a newbie to MISC chip and FORTH, I like FORTH very much. 
>I want to ask if there is MuP21 target computer which can download code
>from PC via RS-232C when we develop system, or operates seperately from
>PC when we copy our code to EEPROM. 

Dr. Ting has designed and offers through Offete Enterprises three
different MuP21 boards.  The development system has a pcmcia card
and a parallel I/O chip and 5 drams.  The second kit pcb uses a uvprom
instead of the pcmcia card and a 32 bit simm instead of 5 drams and
three cmos i/o chips to decode a parallel port.  The third board uses
the PLCC MuP21h and a serial i/o chip and a simmm.  The first two
boards only have one oscilator 14mhz for video.  The third board has
a second oscilator for the serial i/o chip timing.

Any of the boards CAN do serial i/o, but with the first two boards they
must bit bang and unless you add some source of stable timing that the
cpu can read the serial bit bang timing can drift off.  The first 
two boards can run the eForth 2.04 or P21Forth 1.01 or 1.02 which
have serial bit bang i/o.

The third board has no parallel i/o hardware but is designed for
use with a serial connection.

>    I still don't know what I/O can MuP21 use after reading MISC homepage,

MuP21 has only one form of i/o built in, video.  It can generate video
output and that is it.  One can use memory mapped i/o if there is external
hardware to MuP21 that decodes address, data, and control lines to
latch an i/o device when certain memory addresses are touched.  MuP21
can only do i/o other than video with external hardware.  

As I mentioned before Dr. Ting's board show how to use serial and 
parallel i/o chip or design your own memory mapped i/o interface to
whatever...  

But the question is not unlike asking what kind of i/o a Pentium can do.
Nothing really, or anything if you connect it up.  But you don't see
descriptions of the Pentium chip saying it can run a parallel i/o chip
or it can run a serial i/o chip.  We just expect it will do i/o though
a video card, an audio card, a network card, a serial card, a parallel
card, an IDE interface, a pci bus, etc.   MuP21 is no different, it
just has a video card built into the chip.

>can I use PC-compatible Parallel Port and RS-232C? Should I buy an I/O

You can use a parallel port to interface to OK and P21Forth,  you can
user a serial interface to connect to eForth 2.04 or P21Forth.  You 
could even bit bang a serial interface on the parallel port of your
PC if you wanted to, but I wouldn't recommend it.  I would recommend
it more than trying to use a serial connection to the bit banged 
serial on the first P21 boards.  Serial is ok on the third board but
I prefer parallel on the first or second boards.

>board to use Parallel port and RS-232C, or they are built-in? And could

There is a parallel port on the first two boards and serial port on the
third and the first two CAN do serial w/ software.  You cannot buy a
parallel or serial board that you can use on the P21 boards.  If you
have no parallel or serial port on your PC then you will need to buy
a board.

>I use PCMCIA or whatelse storage device? 

I have used a PCMCIA card on any board by just making a socket adapter so it
will connect in the rom socket.  For whatelse you will need to design
the hardware and software.

>    Sorry, last newbie question. What resolution can MuP21 provide on NTSC
>TV set? I don't see data on MISC homepage. 

The resolution is programmable.  We have tried 192x241, 192x482, 384x241,
384x482, but have not yet tried higher resolutions.  You need to use a
clock faster than 14Mhz for higher resolution.  No one has even tried
resolutions above this yet so the upper limits are not yet known.

>    Sorry for asking so many newbie questions, but I really want to use
>MuP21 to do some real things. Thanks in advance. :>
>- --
>Jiunn-Jye Huang(¶À«T³Ç)          E-mail:<u8213006@cc.nctu.edu.tw> 
>                                        <jjhuang@cm.nctu.edu.tw>

>Dept. of Communication Eng.      Phone:+886-3-5726111 x82408/x25509
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Jeff Fox
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