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Understanding Chips on wideband controller 
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TO220 - Visibile

Joined: Wed Aug 27, 2014 6:25 pm
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I'm sure some of you are more apt to answer, but I was wondering if someone could explain the functionality of 2 chips:
- MC98SR12 (Motorola)
- MAX2321 (Texas Instrument)

The MC98SR12 seems to be a UART type chip, but I couldn't find any specs on it. Anyone have a link?

The MAX2321 (on this zt-2 controller/display board) seems to take data in via Rin and send it back out to Rout. The specs made it seem like it was converting TTL/CMOS to Serial or Serial to TTL/CMOS. I don't understand the purpose of feeding it Serial data and then using its Serial data output, unless there's some sort of filter/cleaning of signal effect?

Help is appreciated.

link to the zt-2 controller discussion: viewtopic.php?f=6&t=2267&start=110#p38989
The chips listed above are also on the PCB that feeds an Optrex/kyocera C-51505 LCD - Specs: http://www.kyocera-display.com/SiteImag ... JN_Eng.pdf


Fri Aug 29, 2014 5:56 pm
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LQFP112 - Up with the play
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Joined: Sat Sep 29, 2012 9:16 pm
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Location: Rotterdam, the Netherlands
I'd bet the Motorola chip is a fairly mainstream microcontroller with some oem specific marking on it.
The MAX2321 is just an RS232 line driver.. You use it because official EIA-232 voltage levels are bipolar (+12/-12, but also +5/-5),
So you cant feed this into an MCU's UART directly, and the onboard UART cant generate it either.
I believe this chip puts out +3/-3 levels and accepts upto +/-30

You're not likely to learn much about the function of the wb controller by knowing what IC's it uses, although I must
admit I always like to have a look to see what manufacturers are using myself.

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Fri Aug 29, 2014 8:37 pm
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TO220 - Visibile

Joined: Wed Aug 27, 2014 6:25 pm
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Thanks Ivan for the input - Is there anyway for me to figure out what that 'mainstream' microcontroller is, so that I can lookup the pins?
Or are all QFP microcontroller with a standard pin layout and thus only need to do a lookup based on the number of pins.

What I'm trying to do, by understanding the chips, is to replicate the setup. The wideband controller feeds this board with the max+mc98 with 1 single data wire (Tx I'm guessing?)

If the microcrontroller simply takes the Tx and pushes it to the correct I/O pin for the LCD display, then I guess a simple arduino could replace it.

I don't know if there's an easy way to test that without rebuilding the same thing with an Arduino, capture the Tx data and feed it to the LCD without touching it?


Fri Aug 29, 2014 8:45 pm
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LQFP112 - Up with the play
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Location: Rotterdam, the Netherlands
If I understand correctly your LCD display is not working correctly anymore and you want to fix it.
Are the IC's you mentioned on the LCD or on the controller? Because that's what you posted pictures of earlier.
There is no point in starting with the wideband controller...

If the display is garbled I would first try some basic fault finding.. do a visual inspection of solder joints on the lcd-controller board,
'beep' through the connections from the ecu to the lcd with a multimeter etc.. if all that seems ok, just replace the lcd with a run of the mill one..
Judging from the pics on zeitronix site they have a 16-wire interface to the lcd.. that has your basic Hitachi HD44780 LCD written all over it.

If you do want to make your own display controller you'll need to sniff the data between the lcd controller and the wb controller.. odds are it just
broadcasts all parameters at a set interval, and whatever display they use just picks what data it wants to show (done in the lcd controller board MCU).

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Sat Aug 30, 2014 6:56 pm
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TO220 - Visibile

Joined: Wed Aug 27, 2014 6:25 pm
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You're exactly on the track that I am. I checked all solder joints and even pin-pointed the different solders to the different chip pins. All checked out.
The LCD is actually the 16-pin kyocera C-51505 LCD linked above. I'd like to verify that the LCD really is the problem, by using some sort of simple arduino-like interface to send simple messages to it and see if they display correctly.
If they don't then I'll know it's the LCD. If they do, then well I'll have to figure out how to sniff the packages. I'm hoping It's a simple serial data read and fed to the LCD. But who knows... I'll probably update this once I can 'test' the LCD with one of the arduino clones


Sat Aug 30, 2014 10:50 pm
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