A brief discussion on how to create a programming interface for the LPC1768 using LPC11U35

Form a starting point I looked through the HDK documentation, and released that this is quite a simple circuit.
as my appetite grew, I looked for a way of making it a reality.

Prior to this, I have been looking through the schematics & datasheets for LPC812-MAX,

surprisingly, I found it had all the electronics I needed to make a prototype,

Time for some 'Trans-cycling'

Step 1, remove LPC812, and clean pads, so no shorts,
Step 2, connect some wires between LPC812-MAX board, and target board,
using the MBED/Espresso pins, Gnd, 3V3, Reset, SWDIO & SWCLK, - that's all. Step 3, Re-Flash LPC812-MAX with HDK Software,
Step 4, reset / unplug, New device appears, and installs stuff.
Step 5, compile test program, save to new drive, reset TARGET, job done.

Test over, now for a real PCB

This is not an ideal solution, as the 'programmer' is quite big and unyielding.

So, design a custom PCB.

Using the HDK demo schematic, I stripped out all but minimal parts, and came up with

I have sent the files off to ragworm PCB So I should have them back and built by the end of November. Unfortunately, the PCB was not big enough for the 'MBED Enabled' LOGO !

The pin out I chose was the same as the LPC-Expresso header, that I butcherd some time ago,
I did have the original intention of using the programmer part, but I never got there, as it was not MBED friendly, (as this design).

Whats next ?

I think if (when) i design a second iteration, then the two unused pins (JTAG uses more pins),
will link through to the CDC Serial, and possably USB 5 Volts

This will conveniently match the FTDI 3V3 serial lead, I have been using for serial programming,
with Flash Magic.

which in comparison is PAINFULLY SLOW,
less than 2 seconds for SWD,
verses more than 30 seconds for a reasonable sized program. ..

22 Nov 2013: Don't try this at home !!¶

Just received my PCB's from ragworm.eu (very nice)

Unfortunately, the LPC11U35-48-401 does not have enough memory (10K not 12K)

to allow programming,

but I have not tested debug, because it is on a different PC.

Unfortunately, I need the 64 pin device, to have enough memory.

Which means a new PCB :(

Ceri