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Connecting analog inputs, Related resources – Digilent 410-087P-KIT User Manual

Page 79

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Spartan-3E Starter Kit Board User Guide

www.xilinx.com

79

UG230 (v1.0) March 9, 2006

Disable Other Devices on the SPI Bus to Avoid Contention

R

Disable Other Devices on the SPI Bus to Avoid Contention

The SPI bus signals are shared by other devices on the board. It is vital that other devices
are disabled when the FPGA communicates with the AMP or ADC to avoid bus
contention.

Table 10-4

provides the signals and logic values required to disable the other

devices. Although the StrataFlash PROM is a parallel device, its least-significant data bit is
shared with the SPI_MISO signal. The Platform Flash PROM is only potentially enabled if
the FPGA is set up for Master Serial mode configuration.

Connecting Analog Inputs

Connect AC signals to VINA or VINB via a DC blocking capacitor.

Related Resources

Amplifier and A/D Converter Control for the Spartan-3E Starter Kit (Reference
Design)

http://www.xilinx.com/s3estarter

Xilinx PicoBlaze Soft Processor

http://www.xilinx.com/picoblaze

LTC6912 Dual Programmable Gain Amplifiers with Serial Digital Interface

http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1009,C1121,P7596,D5359

LTC1407A-1 Serial 14-bit Simultaneous Sampling ADCs with Shutdown

http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1155,C1001,C1158,P2420,D1295

Table 10-4:

Disable Other Devices on SPI Bus

Signal

Disabled Device

Disable Value

SPI_SS_B

SPI Serial Flash

1

AMP_CS

Programmable Pre-Amplifier

1

DAC_CS

DAC

1

SF_CE0

StrataFlash Parallel Flash PROM

1

FPGA_INIT_B

Platform Flash PROM

1