================ Board Addressing

Each Opera Cake has a numeric address set by optional jumpers installed on header P1. The default address (without jumpers) is 0. The --list or -l option can be used to list the address(es) of one or more Opera Cakes installed on a HackRF One:

.. code-block:: sh

hackrf_operacake -l

The address may be set to any number from 0 to 7 by installing jumpers across the A0, A1, and/or A2 pins of header P1.

.. list-table:: :header-rows: 1 :widths: 1 1 1 1

• • Address
  • A2 Jumper
  • A1 Jumper
  • A0 Jumper
• • 0
  • No
  • No
  • No
• • 1
  • No
  • No
  • Yes
• • 2
  • No
  • Yes
  • No
• • 3
  • No
  • Yes
  • Yes
• • 4
  • Yes
  • No
  • No
• • 5
  • Yes
  • No
  • Yes
• • 6
  • Yes
  • Yes
  • No
• • 7
  • Yes
  • Yes
  • Yes

When configuring an Opera Cake, the address may be specified with the --address or -o option:

.. code-block:: sh

hackrf_operacake -o 1 -a A1 -b B2

If the address is unspecified, 0 is assumed. It is only necessary to specify the address if the address has been changed with the addition of jumpers, typically required only if multiple Opera Cakes are stacked onto a single HackRF One.