Flashing an MCU with MicroUSB
You can't use a USB connector to download code to one of those ARM chips, the flash bootloader uses the UART.

I've used one of these USB to serial adapters:

http://www.ebay.co.uk/itm/180836792643?ssPageName=STRK:MEWNX:IT&amp;_trksid=p3984.m1439.l2649

with Flash Magic to download code to an LPC810 chip via the UART connections. You have to connect a pin to ground when applying power to enable flash downloading, details will be in the data sheet.