16.12.4 Debug Communication Channels

The Debug Communication Channels (DCC0 and DCC1) consist of a pair of registers with associated handshake logic, accessible by both CPU and debugger with no security restriction. These registers are used to exchange data between the device and a debugger. This enables the user to build a custom debug protocol using only these registers.

The DCC0 and DCC1 registers are always accessible from the external address space. They are used to communicate with the Boot ROM after a cold-plugging procedure. For more information, refer to the Host “Boot ROM”.

Two Debug Communication Channel status bits in the STATUSB register (STATUSB.DCCDx) indicate that a new value has been written into DCC0 or DCC1. These bits, DCC0D and DCC1D, are located in the STATUSB register. They are automatically set by hardware and cleared on read.

Note: The DCC0 and DCC1 registers are shared with the Boot Communication Channels (BCC0 and BCC1) registers, therefore mixing DCC and BCC communication is not recommended.