Hi,
Apologise if stupid question but totally new to this - Trying to upload from Arduino software using USBTTL cable but the version I have is only 4 wire and does not include the RTS and CTS wires. Are these necessary? (I have wired the others to the correct pins) When I connect up and run the Serial monitor I get a constant stream of data from the board when it's turned on but am unable to transfer any information to it. Any help appreciated.

I'm not familiar with this cable version. Do you have a part number or specification?

In any case, you can probably use it to reprogram the board, if you execute a "manual reset" by pressing the reset button just after telling the computer to reprogram the board.

(Regardless, you'll *still* get garbage data from the Peggy to the computer with the serial monitor, unless you've built a Peggy 2.3 or a Peggy 2LE *and* enabled the serial hack option.)

Thanks for quick reply - tried reset button to no avail. Message from Arduino was

avrdude: stk500_getsync(): not in sync: resp=0x19
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x19

swapped Tx and Rx and got:

avrdude: stk500_getsync(): not in sync: resp=0x0a
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x0a

The cable is manufactured came from www.avitresearch.co.uk/usb_to_ttl.htm

Okay--wow. I've never seen one of those before. It doesn't show up in relation to the keyword "Arduino" in a Google search, so you may actually be in uncharted territory here.

Of course, that doesn't mean that it shouldn't work.

First, make sure-- from the documentation --that you have the right pins going to TX and RX. It just won't work otherwise.

Next, the timing on that button press is super important. The Peggy looks for a programmer for only two seconds after the button press, so that two second interval needs to overlap the moment when the computer starts looking for a device to program. It usually starts looking just after it displays the compiled program size-- or 1-3 seconds after that.