Mobile satellite telephony system interface
Mike Randall was able to meet a tight deadline to design a component of NEC Australia's mobile satellite telephony system — an interface within the satellite ground station between the satellite protocols and the land telephone network.
This involved Freescale's MC68360 32-bit communications controller, Texas Instruments' TMS320C31 digital signal processor, a Rockwell MODEM chip set, their individual memory subsystems and a shared dual-ported memory for inter-processor communications. Glue-logic functions were incorporated into PLDs and an Altera FPGA.
The success of this project led to further contracts to redesign this board and the base-band processor board of the mobile telephone unit for a military version.
This involved replacing the FPGAs on both boards with Xilinx Spartan FPGAs to allow for encryption over the air link. The main processor was also upgraded from an obsolescent 16-bit 69341 to the 68360.
Existing communications-related functions in the gate arrays were translated to suit the Xilinx Spartan chips and functionality added to allow the control processor and the DSP to have access to an encryption module.