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R.38 Data Pump Software for Texas TMS320C2xx/C5x DSPs

This software implements the ITU Data Modem function R.38. R.38 provides half-duplex data transmission at rates of up to 200b/s over the telephone network using frequency shift keying. The software is in the form of two callable subroutines, one for initialisation and one for per-sample processing of input/output samples and data bits. The user is responsible for interfacing sample and data input & output to hardware. Blocks of data and samples can be processed by making multiple sub-routine calls. A comprehensive user's guide is provided with the code. Test results are available.

Interfaces: at the sample interface, the code can operate at 9.6kHz or 8.0kHz sample rates. At the data interface, data bits are transferred on a per-sample basis. R.38 is primarily geared towards asynchronous data transfer so the current data bit polarity is transferred at the interface. However, clocks are provided for both transmit and received directions so that, if required, data can be transferred synchronously at 200b/s. At the control interface, one 16-bit control word sequences operations and sets parameters, and one diagnostic word conveys data transfer status.

Performance:

• SNR for 10^-6 error rate at 200b/s: 6dB - Flat Channel
  

DSP Load: parameters given for operation at a 9.6kHz sample rate - operation at an 8.0kHz sample rate requires an extra 0.7MIPs, 30 data memory and 0.3k program memory words:

• MIPS: 2.5

• Data memory: 52 words

• Program memory: 0.6k words

Availability: NOW - sale is under licence - integration support offered