FGM peer PDR I/F - 1 Braunschweig, October 8-9, 2003 Digital Interface (I/F) Aris Valavanoglou Institut für Weltraumforschung (IWF) Austrian Academy of Sciences

FGM peer PDR I/F - 2 Braunschweig, October 8-9, 2003 Command & Data Interface Based on THEMIS IDPU backplane specification Serial protocol synchronized to a 2^23 Hz clock (CLK8MHz) FGE receives its own set of CDI signals CLK (continuous signal provided by DCB) –2^23 Hz (CLK8MHz) –1 Hz (CLK1Hz) Command (CMD) FGE returns messages via two telemetry (TLM) signals –TMH (128 Hz vector rate continuously) –TML (4 … 128 Hz per command)

FGM peer PDR I/F - 3 Braunschweig, October 8-9, 2003 Serial Interface Circuit Two clock signals –1 Hz, 2^23 MHz One Command Line Two Telemetry Lines –High Rate (TMH) –Low Rate (TML) TMH with 128 Hz vector rate  DFB, spin fit calculations TML with 4 … 128 Hz vector rate x2: CLK1Hz and CLK8MHz x2: TMH and TML

FGM peer PDR I/F - 4 Braunschweig, October 8-9, bits long Plus Start, Stop and odd Parity bit (calculated without Start bit) FGE clocks in the data bits on the falling edge of CLK8MHz Data transferred MSB first 8-bit identifier in the MSB (FGE CMD_ID = $8x) 16-bit data field in the LSB (CMD_DATA) Wrong commands rejected but not reported to IDPU Synchronization by first non-zero (Start) bit after 25 zeros Command Interface Command I/F Timing

FGM peer PDR I/F - 5 Braunschweig, October 8-9, 2003 Commands First Part of Commands:

FGM peer PDR I/F - 6 Braunschweig, October 8-9, 2003 Commands Second Part of Commands:

FGM peer PDR I/F - 7 Braunschweig, October 8-9, bit long message word Plus Start bit Message preceded by 17 zeros End of message indicated by Zero instead of Start bit again FGE message consists of 3 x 24-bit vectors Each vector sign extended into 2 x 16 bit words FGE message length is 6 x 16 words (X-MSW, X-LSW, Y-MSW …) Same format for TMH and TML Telemetry Interface Telemetry I/F Timing

FGM peer PDR I/F - 8 Braunschweig, October 8-9, 2003 Synchronization Time Synchronization Constant delay between data acquisition and data transmission (derived from 2^23 Hz CLK) Time stamping done by IDPU Start of data acquisition with one second sync (TBD) Clock Timing