Lpc1549 usb isp

Hello all,

I have just made a new PCB with an LPC1549 - 48 on it.
Absolute minimum parts,

USB connection, P2-12, P2-13

Pull-up’s for:
ISP-0, P0-4
ISP-1 P0-16
I2C, P0-23, P0-22
Serial P0-15, P0-14
12 Mhz Crystal

And 2 LED’s

My problem is it does NOT show up as a USB Device, for programming,
ISP-0 Low & ISP-1 Hi, and a negative going pulse on reset,

with reset low, my board takes about 4mA
When Hi around 9mA

I have made several other PCB designs, with USB enabled chips,
And they have worked OK.

Is there something I am missing, I have searched the data sheet for … you must …

or other Gothcers !!!

I can not see anything in the Espresso board that is relay different,
Other than I am using a 48 pin part not 64 pin part.

I am confident most of the board works, because I can enter serial ISP, and send “?”
and get
“Synchronized” back !!

But of course, using my work PC , I cannot install Flash Magic, or Bin2Hex
Only ‘APPROVED’ software is permitted

Any one has any suggestions,
I would appreciate it,



Hi Ceri,

Since your question doesn’t seem to related to the Mbed OS, I recommend to ask NXP forums here: