Home | Modem Data Pumps | Telephony | Audio | Utilities | Consultancy | Contact Us

V.29 Data Pump Software for Texas TMS320C54x/C55x & C2xx/C5x DSPs

This software implements the ITU Data Modem function V.29, which provides full-duplex data transmission at rates of 9.6, 7.2, & 4.8kb/s over 4-wire leased lines. The software also allows half-duplex transmission over the telephone network for applications such as Group 3 Fax. Good error performance is assured by the use of adaptive equalisation. The software is in the form of two callable subroutines, one for initialisation and one for processing of input /output data and sample blocks. The user is responsible for interfacing sample and data input & output to hardware. By making multiple sub-routine calls, the code can operate on blocks of samples. Data memory is offset-addressed in the ‘C54xC55x version, so the code re-entrant for implementing multiple modems on a single DSP. 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. Transmit and receive samples are transferred on a common clock, to which the transmit clock is synchronised. The receive clock is interpolated in the DSP code for synchronisation to the far-end modem. At the data interface, data is transferred in buffers under pointer control. At the control interface, one 16-bit control word sequences operations and sets parameters, and two diagnostic words convey data transfer and receiver status.

Performance: over flat channels, near matched-filter performance is obtained.

• SNR for 10^-6 error rate at 9.6kb/s: 20.0dB - Flat Channel

DSP Load - 'C54x/'C55x version: parameters given for operation at a 9.6kHz sample rate - operation at an 8.0kHz sample rate requires an extra 0.3MIPS, 20 data memory and 0.2k program memory words:

• MIPS: 3.4

• Data memory: 233 words

• Program memory: 2.0k words

DSP Load - 'C2xx/'C5x version: parameters given for operation at a 9.6kHz sample rate - operation at an 8.0kHz sample rate requires an extra 0.6MIPS, 30 data memory and 0.3k program memory words:

• MIPS: 4.0

• Data memory: 237 words

• Program memory: 2.0k words

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