Freescale Semiconductor MCF5480 - Manual (Page 613)

Controller
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 22-11
22.6.1 EU Access
Assignment of an EU function to a channel is done either statically or dynamically. In the case of static
assignment, an EU is assigned to a channel via the EU Assignment Control Register (EUACR). Once an
EU is statically assigned to a channel, it will remain that way until the EUACR is written and the
assignment is removed.
In the case of dynamic assignment, the channel requests an EU function, the controller checks to see if the
requested EU function is available, and if it is, the controller grants the channel assignment of the EU.
22.6.2 Multiple EU Assignment
In some cases, a channel may request two EUs. The channel will do this by first requesting the primary
EU, then requesting the secondary EU. Once the controller has granted both EUs, this channel is then
capable of requesting that the secondary EU snoop the bus. Snooping is described in Table 22-14 .
In all cases, the controller assigns the primary EU to a requesting channel as the EUs become available.
The controller does not wait until both EUs are available before issuing any grants to a channel which is
requesting two EU functions.
22.6.3 Multiple Channels
Since there are multiple channels in the SEC, the controller must arbitrate for access to the execution units.
Because a channel cannot make instantaneous resource requests, the arbiter in the controller will toggle
between channel 1 and channel 2, assuming that both channels are contesting for a given resource, such as
the external bus or a particular EU.
22.6.4 Controller Registers
The controller contains the following registers, which are described in detail in the following sections.
• EU assignment control register (EUACR)
• EU assignment status register (EUASR)
• SEC interrupt mask register (SIMR)
• SEC interrupt status register (SISR)
• SEC interrupt control register (SICR)
• SEC ID register (SIDR)
• SEC master control register (SMCR)
• Master error address register (MEAR)
22.6.4.1 EU Assignment Control Registers (EUACRH and EUACRL)
These registers are used to make a static assignment of a EU to a particular crypto-channel. When assigned
in this fashion, the EU is inaccessible to any other crypto-channel.
NOTE
The EU assignment control registers (EUACRH and EUACRL) are used to
make, and therefore will reflect, only static assignments.