MCX MicrocontrollersのトピックRe: Using USB via ISP for flashing (MCXA175VLH)

Using USB via ISP for flashing (MCXA175VLH)

KKU — Thu, 01 Oct 2026 11:10:33 GMT

Dear all,

We have migrated an existing design from an LPC1315 to the new MCXA175VLH. We generally use USB in ISP mode to upload the software. This works without any problems with the LPC1315 (and countless other processors). With the MCXA175VLH, however, no message appears after connecting to the PC. The ISP pin P0.6 is set to low, and the RESET pin is also being handled correctly. The two lines, DP+ and DM-, are each connected to the PC via a 33-ohm resistor.

The processor itself is working properly—access via SWDIO works flawlessly—so the debugger works as well.

Any ideas?

Re: Using USB via ISP for flashing (MCXA175VLH)

luis_maravilla — Thu, 01 Oct 2026 22:49:29 GMT

Hello

According to UG10365: MCX A175 Hardware Design Guide Chapter 6.3 ISP Programming and Table 13; The MCX A17 only support Universal Asynchronous Receiver/Transmitter (UART) as Serial Peripheral Interface (SPI) interface. Inter-Integrated Circuit (I2C), SPI, and Universal Serial Bus (USB) ISP interfaces are not supported.

The USB connection won't be read in this context, so please add the UART ISP connection instead.

If you are designing a MCXA175 custom board, please refer to this Hardware design guide for more recommendations and instructions

Best Regards, Luis

Re: Using USB via ISP for flashing (MCXA175VLH)

KKU — Mon, 05 Oct 2026 06:22:24 GMT

Dear Luis,

Thanks for your reply. Could you please share the document in question? The link doesn't work, and I can't find UG10365 anywhere either. In any case, this feature is explicitly described in the current Reference Manual (see above) and elsewhere. I also can't imagine that such a feature (which was already standard in older series) wouldn't be available.

BR, Kay

Re: Using USB via ISP for flashing (MCXA175VLH)

luis_maravilla — Mon, 05 Oct 2026 16:41:46 GMT

Hello,

You need to enter with a NXP account in NXP.com to access the documentation.

Please sign in or Register for an NXP account [In the upper right section of the NXP.com page]

And then in the MCXA17x main page Documentation [User Guide Section] you can look for the [UG10365] or after sign in, enter the link for UG10365: MCX A175 Hardware Design Guide

Best Regards