Execution Units
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-55
then write the key data to AFEU key registers, then write the key size to the Key Size
Register. The AFEU starts permuting the memory with the contents of the key
registers immediately after the key size is written.
26.4.5.3 AFEU Context/Data Size Register
The AFEU context/Data Size Register stores the number of bits in the final message with an
upper bound of 4096. Whatever number is written (and whatever truncated value is stored) must
be a multiple of 8. This value controls how much data is processed from the last block. The last
message block must be a multiple of 8 from 8–64. If you write data size that is not a multiple of 8,
a data size error is generated. Only the 3 lsbs are checked to determine if there is a data size error.
Because all upper bits are ignored, the entire message length (in bits) can be written to this
register.
The context/Data Size Register is also used to specify the context size, when context is used. The
context size is fixed at 2072 bits (259 bytes). When loading context through the FIFO, all context
data must be written prior to writing the context data size. The message data size must be written
separately.
Note:
When reloading an existing context using core processor-controlled access, the user
must write the context to the input FIFO, then write the context size (always 2072 bits).
The write of the context size indicates to the AFEU that all context has been loaded.
The user then writes the message data size to the context/Data Size Register. After this
write, the user may begin writing message data to the FIFO.
Writing to this register causes the AFEU to start processing data from the input FIFO as soon as
it is available. If the value of data size is modified during processing, a context error is generated.
This register is cleared when the AFEU is reset or reinitialized.
26.4.5.4 AFEU Reset Control Register
This register allows 3 levels of reset that effect the AFEU only, as defined by 3 self-clearing bits.
The AFEU executes an internal reset sequence for hardware reset, software reset, or module
initialization, which performs proper initialization of the S-Box. Use the RESET_DONE bit in
the AFEU Status Register to determine when the reinitialization is complete.
26.4.5.5 AFEU Status Register
This Status Register reflects the state of AFEU internal signals. The AFEU Status Register is
read-only. Writing to this location results in address error being reflected in the AFEU Interrupt
Status Register.
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...