A TPU (Time Processing Unit) is a custom piece of silicon available from NXP on a variety of microcontrollers. Because the TPU/eTPU executes code, just like a CPU does, the designer can be led into the mistaken view that the TPU/eTPU is simply a co-processor. Actually, from a design standpoint, the TPU is similar to an ASIC or a FPGA in that a wide variety of circuitry can be replaced with a single device. But, unlike an ASIC or a FPGA, the TPU is free, assuming that the decision to use a microcontroller that contains a TPU such as a 683xx or HC16 has already been made. An eTPU (Enhanced Time Processing Unit) is NXP's successor to the TPU and is available on many MPC5xxx Power Architecture MCUs. Conceptually similar to the TPU, the eTPU contains more channels, has more sophisticated channel hardware, and supports angle mode in addition to timer mode.
The benefit of using the eTPU (or TPU) is its ability to replace external circuitry and thereby save you money.
When considering the types of circuitry that the eTPU can replace, it is important to keep in mind that the eTPU can be programmed using your custom microcode. Thus, many applications for which the eTPU is suited are not supported by a standard mask and are not found in NXP's custom eTPU microcode library. The following is a list of a few notable devices and circuits that the eTPU can replace.
UARTs (RS422, RS485)
ARINC 429 Chipsets
Stepper Motor Controllers
Multiphase Commutation Motor Controllers
Hall Effect Decoders
A/D Converters (A/F into F/D)
When a particular application is not supported by the existing standard library of eTPU code, the developer must create custom eTPU C code. The ASH WARE ETEC eTPU/eTPU2/eTPU2+ C Compiler can be used to create and compile your custom eTPU "C" code. The code can consist of a combination of both the standard library code and your custom eTPU code. ASH WARE Inc.'s eTPU2+ DevTool simulation engine can be used to verify that the eTPU "C" code meets the requirements of the application.
Is ByteCraft eTPU C supported?
The ByteCraft compiler output is supported by our simulation engines, but note that ByteCraft Ltd. no longer in business. Our tools provide a migration path and are fully supported - see the porting guide for more information.
While easier than TPU microcoding, eTPU coding has a learning curve. The eTPU coding course is therefore highly recommended. The cost of approximately $1500 is well worth it. See our web page on training services.
Newcomers to writing custom TPU microcode have been hampered by a dearth of readily available information. Amy Dyson and Munir Bannoura have addressed this issue by publishing a book called "TPU Microcoding for Beginners". For the eTPU there is the book "eTPU Programming Made Easy" - both are available through ASH WARE. Last, the ETEC Compiler manuals, which can downloaded for free from this website, can be a helpful reference.
ASH WARE offers the only commercially available TPU simulator. Capabilities include script and test vector languages, a graphical logic analyzer, and source-level debugging. A free demonstration version is available upon request. ASH WARE's eTPU simulation engine is the debugging tool of choice for companies around the world doing eTPU development - it is part of the eTPU2+ DevTool IDE. Feature-rich, it quickly allows developers to test and debug their code, create regression tests, and characterize performance.
Lauterbach, iSystem and Ashling have commercially available eTPU debuggers. The ASH WARE ETEC eTPU/eTPU2/eTPU2+ C Compiler is designed to work with these tools.
Contact us! ASH WARE has been developing TPU and eTPU software for over 30 years and have worked with many companies in the automotive, industrial, aerospace and industrial arenas.