LPC 2148 FAILED TO AUTOBAUD

[nimish]

I was hoping you could help me. I am using the following:

Board: LPC 2148
Software: Flash Magic (latest version on the website)
USB to serial converter: From Nex Robotics (uses FT232RL).

Flash Magic returns a "failed to autobaud" error while copying the hex file to the board. It gives the same error even while reading the device signature.

This is the product I am using for USB to serial conversion. The development board and the converter are both from this vendor. I downloaded the driver from the link given on the page.
http://www.nex-robotics.com/products/usb-interfacing/usb-to-rs-232-converter.html

I have tried reinstalling the driver as well as changing the COM port number to a different unused one. Nothing seems to work. The COM port does appear in the device manager.

I tried using Realterm to see if I get a response by sending alphabets, but none appear on the screen. The TXD light does glow on the converter each time I type the alphabet.

A week ago, although I used to get the occasional autobaud error, I still managed to burn a few codes onto the board however now it seems to have stopped working completely. Now, I have no clue where the error lies.

Do respond at the earliest.

I have attached the Flash Magic Debug file.

[Andy Ayre]

The debug file only confirms what you are describing, that FM is not getting a response.

Please go back to your terminal approach. Eight bits, no parity, one stop bit (aka 8N1), 19200 baud. Send a single '?'. It should be echoed back but you will find that it isn't.

Put a scope on the RxD pin and check the '?' is arriving. Put a scope on the TxD pin and check if it is being transmitted.

Put a scope on the XTAL pins and check for a waveform. Double check supply voltages, make sure no noise or ripple. Also the reset line. Double-check the voltage at the ISP entry pin and make sure that when you are resetting the part the voltage is going down to zero at the pin.

Most likely cause is electrical - either a bad solder joint or incorrect design.

Andy

[nimish]

Really appreciate the prompt, helpful response, Andy!

Which TXD and RXD do you think I should check? I am using a USB cable, a USB to serial adapter, and a serial cable. Which one out of these? Or all of them?

I am just hoping to narrow this down and hope that it's just a faulty cable because a faulty converter/development board will cost a lot of money as well as time, waiting for the new one to arrive.

[Andy Ayre]

Which TXD and RXD do you think I should check?

The pins on the microcontroller.

[nimish]

Hi Andy,

I went to the technical support team of the place we bought the USB to RS232 connector from and they tested the converter as well as the board. The board is fine but the connector was failing the echo test.

I got a replacement as the debugging would've taken a while so I don't really know what was wrong with it; it could be either of the two ICs- Max232 and FT232RL.

I was told that a possible reason might be that the IC might have been affected by static. So this is for all the others who might happen upon this thread. Do perform the echo test once just to make sure your connector is functioning and avoid direct contact between fingers and the ICs, specially in winters.