VCEU Introduction

The VME Command Encoder Unit (VCEU) is capable of generating various standard spacecraft command formats. The VCEU incorporates a 400K Xilinx FPGA and a Flash Based FPGA Configuration storage device making the VCEU cards a very programmable hardware architecture. The VCEU card’s rich features and resources allow the card to be used and reused for many applications unrelated to spacecraft command/telemetry links

Capabilities:

• Generate Analog and Digital BPSK used by STDN applications
• Generate AM/FSK used by SGLS applications
• Generate Data and Clock digital outputs for STND
• Receive, correlate, and buffer Data and Clock digital inputs
• Generate Ternary digital outputs for SGLS (1,0,S, CLK)
• Receive, correlate, and buffer Ternary digital inputs (SGLS)
• Forward link output buffer of 4K words (8KB) minimum
• Forward link input buffer of 4K words (8KB) minimum
• Provisions for KG61 interface
• Provisions for KIT223A interface
• Automatically inserts 0 to 216 bits of minimum idle data between commands
• Provide programmable STDN idle data, all 1's, all 0's, or alternating 1's and 0's
• Provide programmable SGLS idle data, 1,0,S, NULL
• Provide programmable command rates
• Provide audio output during commanding sequence
• Provide spare RS422 inputs and outputs via main FPGA
• Provide spare 50ohm TTL inputs and outputs via main FPGA
• Provide spare open drain transistor outputs via main FPGA
• Provide spare interfaces directly to P2 from main FPGA
• Interface to VMEbus as A32 D32/D16 slave with interrupter
• Provide selectable VMEbus address decode and IRQ select
• Designed with a large capacity FPGA for easy 
  adaptation to custom applications