12 Replies Latest reply on May 17, 2014 8:33 AM by MichaelF_56

    Information: Programming your BCM20732S-based board from an onboard UART header

    MichaelF_56

      The following pertains to programming your BCM20732S based design outside of the BCM20732S Tag board environment, such as when using something like a FTDI TTL-232R-3V3 USB to Serial Cable (http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm) attached to a UART header designed onto your board.

      First off, note that Serial Wire Debug (SWD) debug/trace messages can also be output through the HCI UART port that’s onboard. The SWD pins are muxed with HCI UART and are used in such a manner that the hardware and firmware can auto-detect the presence of SWD or the HCI host; this means that HCI based download (programming) and SWD (debugging) are mutually exclusive of one another.

      In order to use the onboard UART header and a FTDI TF232R USB to Serial cable to program your custom board, you would need to do the following:

      1.
      With the BCM20732S board powered down, connect the FTDI TTL-232R-3V3 USB to Serial Cable to your PC (USB) then to the UART header on your board: Yellow to RXD, Orange to RXD, Red to VBAT and Black to GND.

      2.
      Power your board up while making sure that RXD is held high during power up. Note that by default this pin is pulled low through an internal 10k ohm resistor.

      3.
      Program the board using the Broadcom IDE just as you would if a BCM20732S Tag board were connected.