VersaLogic VL-EBX-18, Hardware Reference Manual, Page: 49 / 63

Interfaces and Connectors
EBX-18 Hardware Reference manual
42
Analog Input
The EBX-18 employs a Linear Tech LTC1857 A/D device. This device operates off a single 5V
supply to provide eight 12-bit analog inputs. The LTC1857 provides eight single-ended input
channels; or alternatively each even and odd analog channel “pair” (for example inputs 1 and 2
or 5 and 6) can be combined as differential inputs or you can also have combinations of both
single-ended and differential channels. The converter has a 100 kilo-samples-per-second (ksps)
sampling rate, with a 4 μs acquisition time and per-channel input ranges of 0 to 5V, ±5V, 0 to
+10V and ±10V.
Communications with the A/D converter are handled by the FPGA, which uses the SPX slave
selection signal for SPI device 5 to enable the A/D read strobe for the SPI interface. Refer to the
EBX-18 Programmer’s Reference Manual (available on the EBX-18 Product Support Web Page )
for information on configuring the SPX registers for Analog Input.
Refer to the Linear Technology LTC1857 A/D Converter Datasheet for programming
information.
E
XTERNAL
C
ONNECTIONS
Single-ended analog voltages are routed to the J5 Utility I/O connector. These signals are also
accessible if a CBR-4004B paddleboard is attached to the EBX-18. Refer also to Figure 22 on
page 53 to see how the analog signals can be accessed on the CBR-4004B paddleboard.
Table 28: Analog Input Connector
EBX-18 Board J5 Pin Signal CBR-4004B Connector
31 ADCH1
J8 Analog I/O
(See Figure 22 on page 53)
32 ADCH2
33 ADCH3
34 ADCH4
35 ADGND
36 ADCH5
J9 Analog I/O
(See Figure 22 on page 53)
37 ADCH6
38 ADCH7
39 ADCH8
40 ADGND
I
NITIATING AN
A
NALOG
C
ONVERSION
For information on initiating an analog conversion, refer to the EBX-18 Programmer’s Reference
Manual (available on the EBX-18 Product Support Web Page ).