HOLT ADK-8400 Quick Start Manual page 12

2. Press key 'm', a screen similar to the one below should be seen.
External SPI Operation
The HI-8400 devices are normally controlled through the on-board MCU. If required, an external
SPI master connected to J7 can be used. When using this method close jumper J1 to hold the
MCU RESET pin low, this forces the MCU GPIOs into a high impedance state. For normal
operation, keep this jumper open and use the RESET button to reset the MCU during testing.
Power should be connected between the VDD terminal and ground. The SPI controller should
then be connected to J7, using the following pin connections:
SPI Connector (J7)
Pin
Number
1
2
3
4
5
6
7
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The sense data for Device1 on board1 and Device2 on board2 are displayed, a '1' meaning a
high. Key 's' can be used to just do one read. LED[1:8] also monitor the eight input states.
Label
VLOGIC
nCS
SCK
SI
SO
INTB
GND
Holt Integrated Circuits
12
Description
3.3V or 5V Logic supply
SPI Chip Select
SPI Serial Clock Input
SPI Serial Data Input
SPI Serial Output from U3
Interrupt output from U3
Low voltage Ground