Expansion Interfaces
EBX-38 Hardware Reference Manual
47
The table below lists the pinout of the SPX connector.
Table 23: SPX Connector Pinout
Pin
Signal
Function
1
VCC
5V Power (Fused from S0 power in this product)
2
SCLK
SPX Clock
3
GND
Ground
4
MISO
Serial Data input (Master In Slave Out)
5
GND
Ground
6
MOSI
Serial Data output (Master Out Slave In)
7
GND
Ground
8
SS0#
Chip Select 0 (low true)
9
SS1#
Chip Select 1 (low true)
10
SS2#
Chip Select 2 (low true)
11
SS3#
Chip Select 3 (low true)
12
GND
Ground
13
INT#
Interrupt input (low true)
14
VCC
5V Power (Fused from S0 power in this product)
SPI is, in its simplest form, a three wire serial bus. One signal is a clock, driven only by the
permanent master device on-board. The others are Data In and Data Out with respect to the
master. The SPX implementation on the EBX-38 board supports chip selects. The master device
initiates all SPI transactions. A slave device responds when its chip select is asserted and it
receives clock pulses from the master. All four common SPI modes are supported through the use
of clock polarity and clock idle state controls.
The SPI clock is derived from a 33 MHz PCI clock and can be software-configured to operate at
the following frequencies:
8.25 MHz (33 MHz/4)
4.125 MHz (33 MHz/8)
2.0625 MHz (33 MHz/16)
1.03125 MHz (33 MHz/32)
C
ABLING
Adapter cables, part number CBR-1401(Six inch) or CBR-1402 (Twelve inch), are available.
V
ERSA
L
OGIC
SPX
E
XPANSION
M
ODULES
VersaLogic offers several SPX modules that provide a variety of standard functions, such as
analog input, digital I/O, CANbus controller, and others. These are small boards (1.2 inches x
3.775 inches) that can mount on the PC/104 and PC/104-
Plus
stack, using standard PC/104
stand-offs, or up to two feet away from the base board. For more information, contact
