The default SCM space for generated code starts at 0x200. This allows etpu functions 0-7 to be defined in the entry tables.

To allow more entries, this base rom space must be moved. This is done with

#pragma memory ROM [size] @ base_address;

For example:

#pragma memory ROM [0x8000-0x400] @ 0x400;

will allow for space for 16 entries in the eTPU function entry tables.

The compiler has defaults that apply to most eTPU programs, so device header files aren't strictly necessary to compile eTPU programs.

In some situations, you might want to create a header file with configuration statements that alter the compiler's default settings for code memory and parameter RAM. This file is typically described as the "device header file". It must be available to the compiler and BClink (if used).

It's possible to use a Host Service Request to perform initialization, but we don't feel it's the best way.

We recommend using the host interface macros to create an initialization routine to run on the host.

Here is one way:

I declared a static local variable named the same as a function parameter. The compiler didn't catch the error. Is this a bug?

Submitted by Kirk Zurell on Wed, 2007-11-21 16:14. eTPU_C

It's not a bug; it is a problem with the C language itself. The local shadows the parameter.

How do I re-read the Capture registers into ERT1/2? How do I read the Match registers into ERT1/2?

Submitted by Kirk Zurell on Wed, 2007-11-21 16:13. eTPU_C

To refresh ERT1/2 with the value of the Capture registers, re-assign the chan register:

chan = chan;

To load ERT1/2 with the value of the Match registers, use the read_match() intrinsic.

read_match();

How do I enable or disable match events/the ME flag/the PP (parameter preload) flag in an Entry Point?

Submitted by Kirk Zurell on Wed, 2007-11-21 16:11. eTPU_C

Use the intrinsic functions enable_match() and disable_match() to do this.

These functions generate no code. Look for the results in the listing file, in the entry point report following each part of the ETPU_function if()/else if()/else structure.

Enabling matches during a thread

Note: some additional entry report lines deleted for space

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Can I use goto to jump between sections of the if()..else if()..else in an eTPU function?

Submitted by Kirk Zurell on Wed, 2007-11-21 16:09. eTPU_C

In general, no. Remember that the bodies of this top-local-scope statement are individual eTPU threads. The compiler treats them as run-to-completion code, and may optimize them differently.

To share programming between more than one thread within an eTPU function, create a C function and call it from all relevant threads.

C includes a register data type. Does eTPU_C allow register allocations? How do I access the P register from C?

Submitted by Kirk Zurell on Wed, 2007-11-21 16:07. eTPU_C

eTPU_C does offer register-like types, with a few catches. You can use these types to access hardware registers directly, if necessary.

The traditional register alerts the compiler to allocate very fast storage (ie., a processor register) for a variable. It's a suggestion, and not mandatory. register might be useful on a system with lots of similar general-purpose registers. On eTPU, using register types is less of an advantage.

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