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From: rcharlet@gauss.elee.calpoly.edu (Richard Charlet)
Subject: MiniBoard DownLoad Problem 2.0
Message-ID: <1994Nov29.230755.191549@zeus.aix.calpoly.edu>
Sender: news@zeus.calpoly.edu
Organization: Cal Poly State University, San Luis Obispo
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Date: Tue, 29 Nov 1994 23:07:55 GMT
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Howdy,
	
PROBLEM STATEMENT:
	I have a miniboard v2.0 which will not accept a program downloading
into its eeprom. The red LED always stays on (even after sliding the 
run/download switch to the right and pressing the reset button). The 
green LED flashes  during download. DLM always reports the following:
	<Some initial message> 
	a bunch of dots
	"Syncronizing with board"
	a few more dots
	"failed"

MY DIOGNOSTICS SO FAR:
	Actually I have two miniboards, one older one (version 1.1) and the
new one I just got with the problem (extended version 2.0). The old
miniboard downloads programs just fine. I have swaped the MCU chips and 
the downloading problems remains on the new miniboard whereas the old 
miniboard continues to operate fine. I have checked my new miniboard for 
shorts (via checking for the presence of +5V across pin 7 & 14 of the 
7040 chip socket) and I have checked for the presence of about 10Kohm 
of resistance between the TX and RX pins of the RJ-11 jack. (Both checks are
fine).
	I belive the problem is on the miniboard. I believe that my serial
link is fine because I can still download to my old miniboard. I believe that
the MCU is fine because I have swaped it. I believe that both the slide swith
and the reset switch are operating fine because I have checked them with an
ohm meter (my actual check here involves verifying that the swithces on 
my new broken miniboard v2.0 behave exactly the same as on my old working 
miniboard v1.1).

MY LAME THEORY:
	I quote the following paragraph from a file named mbextend.txt 
found on cherupaka:
"* TTL-level 6811 TxD and RxD pins exposed to female header jacks.
    These can be used to communicate with other TTL level async serial
    devices, or can be temporarily jumpered together and tied via 10K
    resistor to +5v to allowing booting of 512 byte of EEPROM 'A1
    versions of the 6811."

	I am not sure that I understand what the above is saying. Does it
have any impact on my situation?

	Can anyone help me out here and suggest what may be wrong?



Thanks in advance

Rick Charlet
rcharlet@gauss.calpoly.edu
