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MPC603e & EC603e RISC Microprocessors User's Manual
MOTOROLA
Integrated power management
— Low-power 2.5-volt and 3.3-volt designs
— Internal processor/bus clock multiplier ratios as follows:
– 1/1, 1.5/1, 2/1, 2.5/1, 3/1, 3.5/1, and 4/1 (PID6-603e)
– 2/1, 2.5/1, 3/1, 3.5/1, 4/1, 4.5/1, 5/1, 5.5/1, and 6/1 (PID7v-603e)
— Three power-saving modes: doze, nap, and sleep
— Automatic dynamic power reduction when internal functional units are idle
In-system testability and debugging features through JTAG boundary-scan
capability
Features specific to the PID7v-603e follow:
Enhancements to the register set
— The PID7v-603e adds two new bits to the HID0 register:
– The address bus enable (ABE) bit, bit 28, gives the PID7v-603e
microprocessor the ability to broadcast
dcbf
,
dcbi
, and
dcbst
onto the 60x
bus.
– The instruction fetch enable M (IFEM) bit, bit 24, allows the PID7v-603e to
reflect the value of the M-bit onto the 60x bus during instruction translation.
— The Run_N counter register (Run_N) has been extended from 16 to 32 bits.
Enhancements to cache implementation
— The instruction cache is blocked only until the critical load completes (hit under
reloads allowed).
— The critical double word is simultaneously written to the cache and forwarded to
the requesting unit, thus minimizing stalls due to load delays.
— Provides for an optional data cache operation broadcast feature (enabled by the
HID0[ABE] bit) that allows for correct system management utilizing an external
copyback L2 cache.
— All of the cache control instructions (
icbi
,
dcbi
,
dcbf
, and
dcbst
, excluding
dcbz
) require that the HID0[ABE] configuration bit be enabled in order to
execute.
Exceptions
— The PID7v-603e now offers hardware support for misaligned little-endian
accesses. Little-endian load/store accesses that are not on a word boundary, with
the exception of strings and multiples, generate exceptions under the same
circumstances as big-endian accesses.
— The PID7v-603e removed misalignment support for
eciwx
and
ecowx
graphics
instructions.These instructions cause an alignment exception if the access is not
on a word boundary.