LPC MicrocontrollersのトピックRe: Boot from USB help

Boot from USB help

lpcware — Wed, 15 Jun 2016 18:25:31 GMT

Content originally posted in LPCWare by jb111 on Sun Dec 13 20:23:43 MST 2015
Hi,

I am trying to boot from USB0, but am having some difficulty.

My setup is a s follows:
- LPC1837
- LPCXpresso
- Ubuntu 15.04

I am happy with the hardware connections. I have verified that USB0 is working by running the Virtual communication port example. The pins to select the boot mode (P2_9, P2_8, P1_2, P1_1) have been checked to be fine (low, high, low, high respectively.)

When I hold the boot pin(P2_7) low on a reset I can see the micro entering the bootrom (flashing LED stops flashing).

But when I run lsusb or dmesg I dont see anything. My understanding is that the USB should enumerate as a DFU device. Is this correct? Is there anything else I have missed?

Thanks.

Re: Boot from USB help

lpcware — Wed, 15 Jun 2016 18:25:32 GMT

Content originally posted in LPCWare by lpcxpresso-support on Mon Dec 14 05:06:10 MST 2015
The most likely issue is that your board is infact booting from Internal Flash - since this will take priority in the boot story if a valid image is detected within either bank of internal flash.

The solution is to either erase the internal flash banks or to boot from ISP.

To erase the internal flash banks, the easiest scheme is to use the project wizard to create a simple project targeted at the LPC1837 - this will by default create a project for the internal BankA flash. Then with this project selected, use the GUI flash programmer and select the Erase flash memory tab, and mass erase the internal flash.

To boot from ISP mode refer to the FAQ below:

https://www.lpcware.com/content/faq/lpcxpresso/regaining-debug-access

Depending on you board design, there may or may not be an ISP reset (button) available.
On Keil MCB boards this is located next to the Reset button.
On LPCXpresso boards this is located at the top the board, about on 1/3 in from the left hand side.

The User manual provides a flowcharts for the boot process for parts with and without internal flash, these should explain in much more detail.

http://www.nxp.com/documents/user_manual/UM10430.pdf

Yours,

LPCXpresso-Support

Re: Boot from USB help

lpcware — Wed, 15 Jun 2016 18:25:32 GMT

Content originally posted in LPCWare by jb111 on Mon Dec 14 20:47:26 MST 2015
Thanks for the reply.

I am using a custom board with control of the ISP entry pin and the nRESET pin.

I have tried both the mass erase of internal flash and booting from ISP mode.

When I do the mass erase, reset and plug in the USB (or have the cable connected the whole time), there is still no enumeration.

I can enter ISP mode and program the device with Flash Magic over UART0, and the downloaded program run correctly.

Programming over UART0 works with the boot pins jumpered for USB0 boot mode. Does this imply that there is a problem with the boot pins and are in fact not at the correct levels? Following the flow diagram in the User Manuel (ch 4 - Fig 10 -Boot process flowchart for LPC18xx parts with flash) seems to imply this.

Thanks again for any help provided,
Regards.