Channels
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 22-19
store the ciphered data the EU outputs. Through a series of requests to the controller, the crypto-channel
decodes the contents of the descriptors to perform the following functions:
Request assignment of one or more of the several EUs for the exclusive use of the channel.
Request assignment of the MDEU when the descriptor header calls for multi-operation processing.
The MDEU will be configured to snoop input or output data intended for the primary assigned EU.
Reset assigned EU(s).
Automatically initialize mode registers in the assigned EU upon notification of completion of the
EU reset sequence.
Automatically initialize the key and key size in the assigned EU after requesting a write to EU key
address space.
Automatically initialize data size in the assigned EU before requesting a write to EU FIFO address
space.
Transfer data packets (up to 32Kbytes) from system memory (master read) into assigned EU input
registers and FIFOs (EU write).
Transfer data packets (up to 32Kbytes) from assigned EU output registers and FIFOs (EU read) to
system memory space (master write).
Release assigned EU(s).
Automatically fetch the next descriptor from system memory and start processing, when chaining
is enabled. Descriptor chains can be of unlimited size.
Provide feedback to host, via interrupt, when a descriptor, or a chain of descriptors, has been
completely processed.
Provide feedback to host, via modified descriptor header write back to system memory, when a
descriptor, or a chain of descriptors, has been completely processed.
Provide feedback to host, via interrupt, when descriptor processing is halted due to an error.
Detect static assignment of EU(s) by the controller and alter descriptor processing flow to skip EU
request and EU release steps. The channel will also automatically reset the EU_DONE interrupt
after receiving indication that processing of input data has been completed by the EU.
The channel will wait indefinitely for the controller to complete a requested activity before continuing to
process a descriptor.

22.7.1 Crypto-Channel Registers

Each crypto-channel contains the following registers:
Crypto-channel configuration register (CCCRn)
Crypto-channel pointer status register (CCPSRn)
Current descriptor pointer register (CDPRn)
Fetch register (FRn)
Data packet descriptor buffer (CFBUFn)

22.7.1.1 Crypto-Channel Configuration Registers (CCCRn)

This register contains five operational bits permitting configuration of the crypto-channel as shown in
Figure 22-16.