Laird BL654 and JTAG


I am new to this, please forgive the simple question.

I need to put a JTAG / USB connector so I can program a BL654 chip from my PC. Can anyone help as to what components I need?

Best Regards,

Hi Adrian,

From the BL654 datasheet, starting on page 32, it discusses this. They recommend you wire out SWDIO, SWDCLK, GND and VCC.

They actually recommend the user purchase the Laird Development board for the BL654, either the 455-00001 (integrated antenna version) or the 455-00002 (external antenna version) and using one of the development board’s connectors (JP1) to program external devices. JP1 is not populated, but we sell it here:


Use this same header on your target board and connect the pins mentioned above as follows:


Using the development kit gives you the advantage of having a known-good board upon which to evaluate and start to develop your application. However, if you already have a separate JTAG device, you can use that rather than the development board.

Thank you very much!

So basically I will have an FTSH-105 on my own board that I can connect via cable to the dev kit.

Best regards,

Yes, that is correct. If I wasn’t clear before, you also need to solder that same connector onto the appropriate spot on the development board because JP1 is not populated.

You will also need a cable assembly to connect the two headers together. Here is a link to some options, with lengths ranging from 6 inches (152mm) to 12 inches (305mm):

JTAG programming cables

I would recommend using the shortest length which works for you, as longer length cables are more likely to have signal integrity issues than shorter ones.