SRAM and orLCD problem Hi,

I'm tring to assembly a Handy board and I get to section 6. "The beeper and
LCD circuit". 
In section 4 I've got the pcode_hb downloaded in the 68HC11A1 and the error
when DL.EXE comes in the second phase. (I use the DOS version from Randy
Sargent on a 486SX Intel machine)  Now I got stuck with the LCD. I don't get
interactive C V 2.81 9/29/93, I get 16 black characters on the first row.
Also the charge LED was flickering on and off or was shining very weak. 

I have checked all the addresslines, datalines, control lines for breaks,
tripled checked the orientation or more the HC132, HC373 and the SRAM. Tried
another , SRAM, 74HC132, the LCD, and checked 74HC373. 

That was all OK I have deassembled the board to section four so the SRAM is
not on it. Download the pcode_hb.s19 again. The strange thing now is that I
don't get the error again when DL.EXE comes in the second phase when it
tries to access the memory. Why???

Also the GREEN PWR led (or TX led) is in the first phse of DL flickering on
and off but in the second phase almost not. Does the first phase hang up up
the download protocol of DL.EXE? 


This is what DL print on the monitor screen:

C:\\IT\\IC\\dl pcode_hb.s19
6811 s19 file downloader version 7.31 1994
	Copy right Randy Sargent 1994
using port com 1
 
Please place the board in download mode and press return,
To quit, press Q
For help, press h
Downloading 256 byte bootstrap (229 data)
.....................................................................
.....................................................................
.....................................................................
........................................_____________________________
Download succesfull
Config 0x0C
loading pcode_hb.s19

Sending pcode_hb.19
.....................................................................
.....................................................................
.....................................................................
...................................................................Done.
Press the board RESET button to start pcode_hb.s19
Press any key to exit...
Bye!
)


Finally tried another processor and another SRAM. I don't see the flickering
now with the other SRAM so maybe the SRAM is defected but with the other
processsor and the SRAM I still don't see Interactive C on my LCD. The LCD's
I use is a 2 row*16 and a 1*16. The one row gives 8 black blocks on it's
row. It is possible that these are defect because this where not new but the
2*16 I got from my work of the shelff?

I'm wandering if it could be the 
a)	PCODE_HB.S19 or the downloader? Should I use DLM in stead off DL? 
b)	Can it be the contrast of the LCD?
c)    Can it be the MC34064HC Reset circuit? ( I have used this one because
the DS1233-10 is hard to get hear in the Netherlands) Therefore I have also
let out the BATT led (and connected the tow holes of the LED to each other
so that the reset output is pulled up to VCC with the resistor)

Other questions I have is:

1) Why is MODB connected to GND instead of VCC? In the Motorola spec
MC68HC11A8 the normal Handy Board is the special test operating mode. It
says in this section (when MODB=GND) that it is getting his interupt and
reset vectors out of external memory locations BFC0-BFFF instead of internal
memory FFC0-FFFF. I don't know what the PCODE_HB.S19 does but this seam
strange to me.  When you connect MODB to VCC it is in the expanded
Multplexed mode. and then the reset and interrupt vectors is got from
internal memory.

Getting back to my first problem, when I connect MODB to VCC ( by connecting
it to MODA) I see the R/W# toggle on my oscillescoop and see the green PWR
led go on and off ones a second. That assumes that the processor is
executing the PCODE_HB startup code and tries to tranmit data to the PC.
When I connect it to ground the level of the R/W# pin stays at 5 volt and I
see glitches from about one volt around the steady high level.

2) Is it possible to zip the archive files. I would be much easier to
download them and review them locally.

3) I'm a newbee with a mailing list, sorry and sorry for asking but when I'm
joining this list do I get hundreds of email every day or do you get ones a
week the latest emails or how those this works? I don't know if I should
join this list but the archives have already helped me lot.

I hope any one is formilliar with this thing and can help me out. Please
send email to: eleenman@lucent.com

Thanks in advance and greetings from the lowlands in the Netherlands.

Eric Leenman

