Specifications

080505 OPERATIONS MANUAL PPM-GX500 11
Audio Interface
The PPM-GX500 has an audio interface designed to provide high-quality audio
reproduction for embedded systems use. The PPM-GX500 provides a 2-channel line
level input, 2-channel line level output and microphone input.
J102 (on the bottom side of the board) provides connection to the audio interface.
Visual
Index
GPS Interface
The PPM-GX500 board has provisions for supporting the Lassen
®
IQ GPS receiver
module. The necessary serial interface is terminated to an 8-pin header connector
(J108) compatible with the GPS receiver. The receiver module and a sample antenna
are available from WinSystems (Part# KIT-GPS-1). Contact your WinSystems’
Applications Engineer for additional information.
The optional GPS can also provide a pulse per second (PPS) interrupt. The receiver
generates a 4 µs wide, positive pulse every second with the leading edge synchronized
to UTC time within ±95 ns when valid position xes are being reported. WinSystems’
on-board implementation degrades this accuracy by buffering the PPS output using
a 74HCT14 Schmitt trigger device which also inverts the signal. Since PC interrupts
are edge-triggered on the rising edge, the actual interrupt will occur 4 µs plus the
inverter propagation time later (typically 17 nS). This added delay is insignicant to
any software synchronizing routines as the entire hardware interrupt acknowledgement
process will consume many additional microseconds in a best-case scenario. The PPS
signal begins immediately at power-up and continues even if the receiver loses GPS
lock. The drift of the signal without GPS lock is unspecied.
Visual
Index
LINE_L LINE_R GND OUT_L OUT_R
GND GND GND
MIC1
MIC1_PWR
J102
9 7 5 3 1
o o o o o
o o o o o
10 8 6 4 2