Disable Other Devices On The Spi Bus To Avoid Contention; Connecting Analog Inputs; Related Resources - Xilinx MIcroBlaze Development Spartan-3E 1600E Kit User Manual

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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.
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.
Table 10-4: Disable Other Devices on SPI Bus

Connecting Analog Inputs

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

Related Resources

MicroBlaze Development Kit Spartan-3E 1600 Edition User Guide
UG257 (v1.1) December 5, 2007
NET "AD_CONV" LOC = "P11" | IOSTANDARD = LVCMOS33 | SLEW = SLOW | DRIVE = 6 ;
NET "SPI_SCK" LOC = "U16" | IOSTANDARD = LVCMOS33 | SLEW = SLOW | DRIVE = 8 ;
NET "SPI_MISO" LOC = "N10" | IOSTANDARD = LVCMOS33 ;
Figure 10-8: UCF Location Constraints for the ADC Interface
Table 10-4 provides the signals and logic values required to disable the other
Signal
SPI_SS_B SPI Serial Flash
AMP_CS Programmable Pre-Amplifier
DAC_CS DAC
SF_CE0 StrataFlash Parallel Flash PROM
FPGA_INIT_B Platform Flash PROM
Amplifier and A/D Converter Control for the Spartan-3E Starter Kit (Reference
Design)
http://www.xilinx.com/sp3e1600e
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
Disable Other Devices on the SPI Bus to Avoid Contention
Disabled Device
UG257_10_08_061406
Disable Value
1
1
1
1
1
81
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