Rapid software development

Product: Full-rate GSM speech transcoder
TI DSP: TMS320C54x
Third party: Signals and Software Limited
Success achieved: TMS320 third-party development expertise    implemented in a full-rate GSM speech transcoder in a short time    using restricted system resources.

Recently, Signals and Software Limited was requested to produce an optimized implementation of the full-rate GSM (FR-GSM) speech transcoder for the TMS320C54x. The software was to include and be compliant with both the transcoder 06.10 and the voice activity detector (VAD) 06.32 ETSI specifications. Finished code had to be delivered three weeks from the start of the project.

The software was developed using a TMS320C541 evaluation module and supplied tools, combined with a custom development and test environment created by Signals and Software. The entire transcoder was written in assembler with a test harness written in C.

The total time required to produce an initial implementation of the encoder, VAD and decoder was 11 days. Final testing, optimization and code reviews brought the required resources to less than the customer’s target requirements for loading and memory. Signals and Software’s expertise, combined with TI’s development ease, made it possible to ship fully documented and reviewed source code days before the customer’s aggressive deadline.

* Dynamic memory can be overlaid into the same memory locations.

The MIPS figures are calculated based on the largest number of cycles required to process the most demanding single frame from the ETSI supplied test vectors. Given the likely path coverage of the test vectors these figures represent the maximum expected MIPS required for the software.