Subject:
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Re: SRAM and orLCD problem
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 15 Dec 1998 13:27:49 GMT
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Original-From:
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Fred G. Martin <FREDM@MEDIA.MIT.EDUantispam>
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Viewed:
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1439 times
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eric, i don't have a definitive answer, but here are two things:
1. You *NEED* the reset chip, whether it's a DS1233 or the MC34064HC,
I don't care, but you must have a device that asserts reset (pulls the
line low) when the system voltage falls below 4.5v. Otherwsie, the
RAM will not hold its contents when you turn the board off.
So, plesae get the proper component, and remove your jumper from the
BATT LED. Put an LED in there!
2. The board is *designed to operate in special test mode*!! So make
sure MODB is connected to Ground!
there is more information about the design of the 6.270 board (which
is the precursor to the Handy Board) in the Appendix B document at:
http://el.www.media.mit.edu/projects/handy-board/techdocs/
Please read it.
Fred
In your message you said:
> 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
>
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Message is in Reply To:
 | | 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 (...) (26 years ago, 15-Dec-98, to lugnet.robotics.handyboard)
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