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633 linux "Timed out waiting for a response." but honors commands

rraszews

New member
I've been playing around with a serial 633 that I've hooked up via a USB to Serial converter. Using the linux example program, I'm getting some rather strange results: the LCD changes as it's supposed to (The text on the screen changes to say 'this is line 1', 'this is line 2'. If the "clear" parameter is given, the screen clears instead), but the output I get to my terminal is:
Ultra-simple CFA-631 / CFA-633 / CFA-635 command-line communications example.
Crystalfontz America, Inc. http://www.crystalfontz.com

Usage:
./example-633 PORT BAUD
PORT is something like "/dev/ttyS0" or "/dev/usb/ttyUSB0"
BAUD is 19200 or 115200
To clear the display, enter "clear" as an optional third parameter

Serial_Init:: success
"/dev/ttyUSB0" opened at "19200" baud.

Timed out waiting for a response.
Timed out waiting for a response.
It never reports receiving any packets back from the LCD, so I can't do things like read button presses. lcd4linux similarly goes into paroxisms because it's not getting responses to any of its commands.

Now, my natural first inclination is that the connection is bad or I've otherwise screwed up my wiring, but here's the *really* weird part:


Just on a lark, I tried "cat /dev/ttyUSB0" and pressed a button. Out popped an 8 byte sequence: 40 80 f8 71 40 80 9d d0, and it consistently produced similar sequences of bytes whenever I pressed a key. Next, I tried catting ttyUSB0 while the example program was running, and again, it was producing output. All this says to me that, yes, the LCD is sending response packets, but something in the software is failing to capture them.

My guess is that this might be some sort of version difference in how the serial interface works. Has anyone run into this or have a solution?

My setup:

Crystalfontz 633 HW 1.3 FW 1.5, connected using USB to serial converter on /dev/ttyUSB0
Ubuntu Intrepid Ibex (8.10), linux 2.6.27-11-generic
Looking for additional LCD resources? Check out our LCD blog for the latest developments in LCD technology.
 
Just on a lark, I tried "cat /dev/ttyUSB0" and pressed a button. Out popped an 8 byte sequence: 40 80 f8 71 40 80 9d d0, and it consistently produced similar sequences of bytes whenever I pressed a key.
A key press or a key release will each send 5 bytes, starting with 0x80, 0x01. So an 8 byte sequence suggests the driver for the usb is not handling the receive packet correctly. The CFA sample software may be timing out because a legitimate packet is not detected.

I have no problem using a CFA633 -> rs232 to usb converter -> Win2K running 633WinTest.
 

rraszews

New member
One small correction; when I looked at the output, my hex editor was set to byte-swap. The actual values it produced were:

8040 71f8
8040 d09d
 
USB LCD Displays - Graphic and Character LCDs with a Keypad

rraszews

New member
Okay, I found that plugging it into another (also Ubuntu 8.10) system resolved the problem, thought I'd still like to know what caused it. I assume it's some kind of dodgy driver or something. Is it possible that the USB line isn't getting enough power?
 
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