Enhanced Time Processing Unit (eTPU)MPC5566 Microcontroller Reference Manual, Rev. 218-8 Freescale Semiconductor18.1.4.6 MicroengineThe eTPU microengine is a simple RISC implementation that performs each instruction in a microcycleof two system clocks, while pre-fetching the next instruction through an instruction pipeline. Instructionexecution time is constant for the arithmetic logic unit (ALU) unless it gets wait states from SDMarbitration.Microcode is stored in shared code memory (SCM) that is 32 bits wide. The microengine instruction setprovides basic arithmetic and logic operations, flow control (jumps and subroutine calls), SDM access, andchannel configuration and control. The instruction formats are defined in such a way that allow particularcombinations of two or three of these operations with unconflicting resources to be executed in parallel inthe same microcycle, thus improving performance.The microengine also has an independent multiply/divide/MAC unit that performs these complexoperations in parallel with other microengine instructions.Channel functionality is integrated into the instruction set through channel control operations andconditional branch operations, which support jumps/calls on channel-specific conditions. This allowsquick and terse channel configuration and control code, contributing to reduced service time.18.1.4.7 Dual eTPU Engine SystemThe MPC5566 eTPU implementation includes two eTPU engines sharing SDM and the same code in theSCM.The two eTPU engines share the bus interface unit (BIU) and the shared data memory (SDM). This allowsthe MPC5566 core to communicate with the eTPU and also provides a means of communication betweenthe eTPU engines. The shared BIU includes coherency logic which supports dual parameter (8 bytes)coherency in transfers between the host and eTPU, using a temporary parameter area within the SDM.18.1.4.8 Debug InterfaceNexus level 3 debug support is available through the eTPU Nexus development interface (NDEDI). Referto Chapter 25, “Nexus Development Interface.”18.1.5 FeaturesThe eTPU includes these distinctive features:• Up to 32 channels for each eTPU engine: each channel is associated with an I/O signal pair— Enhanced input digital filters on the input pins for improved noise immunity. The eTPU digitalfilter can use two samples, three samples, or work in continuous mode.— Orthogonal channels, except for channel 0: each channel can perform any time function. Eachtime function can be assigned to more than one channel at a given time, so each signal can haveany functionality. Channel 0 has the same capabilities of the others, but can also work withspecial angle counter logic.— A link service request allows activation of a channel thread by request of another channel, evenbetween eTPU engines.
