LPC1347: Help with Firmware Update with IAP Command 57

[lpcware]

Content originally posted in LPCWare by BPC on Fri Jun 06 09:28:18 MST 2014
Hello,

I am using the LPC1347 as a CDC device.  To update firmware, I have implemented IAP / ISP Command 57 to reset the device as a Mass Storage Device.  This works very well and I can repeat the process over and over (i.e. 100 times) without any reliability issues.

I have recently observed a situation where I let the board run in CDC mode for a long period of time (i.e. 24 hours) and then call the firmware update command.  In this situation, the board does not reconnect as a Mass Storage Device.  The USB_CONNNECT line does not activate which I can see by the absence of the LED illumination in the USB Soft Connect implementation.  After the WDT resets the board (even though no firmware was update), I simply issue the command a second time and it works perfectly.

Does anyone know what could cause this behavior? 

Thank you.

[lpcware]

Content originally posted in LPCWare by BPC on Fri Jun 06 16:24:33 MST 2014
I was able to figure out the root cause.  I'm using CT32B1 as a motor driver interrupt.  In this, I was setting MCR to 3 (interrupt and reset on MR0).  Since the ISP command handler uses CT32B1, this was causing issues.

The ISP function would work fine if I did not call my step motor function before calling ISP.

In my ReinvokeISP() function, I now simply set LPC_CT32B1->MCR = 0;

This has resolved the issue.

[lpcware]

Content originally posted in LPCWare by mubes on Fri Jun 06 16:14:42 MST 2014
Hi,

What do you have going on with P0_3, which is the bit that decides if it goes to USB or UART ISP mode?

Dave