Datasheet

National Semiconductor Page 10 www.national.com
GPSI Connector (J6) Pin Description
Pin
#
Signal Name/Function
Voltage
Level
Direction (From
SPIO-4)
Pins 1-16 form the GPSI-16 subset:
1 SCS0_A~
SerialBus A – Chip Select for device 0.
1.65 to
5.5V
OUTPUT
2 GND
3 SCK_A
Serial Bus A – Serial Clock from the master to the device.
1.65 to
5.5V
OUTPUT
4 DUT_Present~
The DUT board shall ground this pin. The SPIO-4 senses this pin to
determine the DUT board’s presence.
N/A INPUT
5 SMISO_A
Serial Bus A – Data from the slave (device) to the master. The device
may implement this as a tri-state signal that can be driven by multiple
devices on Serial Bus A in a bussed fashion. The pull-up resistor, if
required, is on the DUT board.
1.65 to
5.5V
INPUT
6 Dev_INT~/SDRDY_A~
In certain applications, if required, this pin serves as the DRDY~
signal from the DUT to the SPIO-4. In other cases, this pin may be a
general interrupt pin from the device to the SPIO-4.
On the SPIO-4 board this signal connects to an interrupt pin on the
microcontroller.
1.65 to
5.5V
INPUT
7 SMOSI_A
Serial Bus A – Data from the master to the slave (device).
1.65 to
5.5V
OUTPUT
8 SCS1_A~
SerialBus A – Chip Select for device 1.
1.65 to
5.5V
OUTPUT
9 Ref_CLK
Reference clock from the DUT board to the SPIO-4 board.If not used,
the DUT board should ground this pin.
1.65 to
5.5V
INPUT
10
GND
11 SDA
Data line of the I2C bus.
Pulled-up to +3.3V_DUT on the SPIO-4 board through a 1.5k resistor.
3.3V Birdirectional
12 SCL
Clock line of the I2C bus.
Pulled-up to +3.3V_DUT on the SPIO-4 board through a 1.5k resistor.
3.3V Birdirectional
13 +3.3V_DUT
Switched by the SPIO-4 conditional on the DUT_Present~ having been
seen. The ID EEPROM and the entire I2C bus on the DUT board must
be unconditionally powered by this supply. Max. peak current: 50mA
(subject to total power budget limit of 200mW over both supplies).
Maximum capacitor loading for this node is not to exceed 50uF.
3.3V OUTPUT
14 +5V_DUT
This supply is sourced by the SPIO-4 and is intended to power the core
functionality of the DUT board – if desired. Nominal current: 35mA.
Max. peak current: 50mA (subject to total power budget limit of
200mW over both supplies). If power from the SPIO-4 is not required,
5.0V OUTPUT