PXD20RM Datasheet, PDF (629/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

• Precise exception handling
• Branch processing unit (BPU)
— Dedicated branch address calculation adder
— Branch target prefetching using an 8-entry branch target buffer (BTB)
• Supports independent instruction and data accesses to different memory subsystems, such as
SRAM and flash memory by means of independent instruction and data bus interface units.
• Load/store unit
• 64-bit general-purpose register file
• Dual advanced high-performance (AHB) 2.v6 64-bit system buses
• Memory management unit (MMU) with 16-entry fully associative TLB and multiple page-size
support
• 4 KB, 2/4-way set-associative instruction cache
• Signal processing extension unit, version 1.1 supporting SIMD fixed-point operations using the
64-bit general-purpose register file
• Embedded floating-point (FPU) unit, version 2 supporting scalar and vector SIMD
single-precision floating-point operations using the 64-bit general-purpose register file
• Nexus Class 3+ real-time development unit
• Power management
— Low power design—extensive clock gating
— Dedicated power saving state: wait
— Dynamic power management of execution units, cache, and MMU
See the following sections for more details about specific units.
15.2.1 Execution Unit Features
The following subsections describes the execution units’ main features.
15.2.1.1 Instruction Unit Features
The instruction unit features the following:
• 64-bit path to cache supports fetching of two 32-bit Power ISA instructions or four 16-bit VLE
instructions per clock cycle.
• Instruction buffer holds up to eight 32-bit Power ISA instructions or sixteen 16-bit VLE
instructions.
• Dedicated program counter (PC) incrementer supports instruction prefetches.
• Branch unit with dedicated branch address adder and branch target buffer supports single-cycle
execution of successfully predicted branches.
Freescale Semiconductor
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
15-3