Analog Input; External Connections; Analog Input Using The Spi Interface - VersaLogic Iguana VL-EPIC-25 Reference Manual

Analog Input

The Iguana uses a multi-range, 12-bit Linear Technology LTC1857 A/D converter with eight
single-ended input signals (even and odd analog channels, for example inputs 1 and 2, can also
be combined as differential inputs). The converter has a 100 kilo-samples-per-second (Ksps)
sampling rate, with a 4 µs acquisition time, with per-channel input ranges of 0 to +5V or 0 to
+10V unipolar, and ±5V or ±10V bipolar
The Iguana A/D converter is controlled using the SPI registers. The A/D converter is accessed
via SPI slave select 5 (writing 5h to the SS field in SPICONTROL).
See "SPI Registers" for a complete description of the registers.
See the Linear Technology LTC1857 A/D Converter Datasheet
Warning!
Application of analog voltages greater than +25V or less than -25V can damage
the converter.
E C
XTERNAL ONNECTIONS
Single-ended analog voltages are applied to connectors J1 and J2 of the VL-CBR-4004 board
(connected to J25 of the Iguana) as shown in the following table.
A I
NALOG NPUT
See "SPI Registers" for a description of the SPI interface and registers.
VL-EPIC-25 Reference Manual
Table 18: Analog Input Connector
J25
Pin Signal
1 Analog Input 1
2 Analog Input 2
3 Analog Input 3
4 Analog Input 4
5 Ground
6 Analog Input 5
7 Analog Input 6
8 Analog Input 7
9 Analog Input 8
10 Ground
U SPI I
SING THE NTERFACE
for programming information.
VL-CBR-4004 VL-CBR-4004
Connector Pin (Label)
J1 5 (IO1)
Analog Input 4 (IO2)
3 (IO3)
2 (IO4)
1 (GND1)
J2 5 (IO5)
Analog Input 4 (IO6)
3 (IO7)
2 (IO8)
1 (GND1)
Interfaces and Connectors
47