92 www.xilinx.comSpartan-3A/3AN FPGA Starter Kit Board User GuideUG334 (v1.1) June 19, 2008Chapter 12: SPI Serial Flash RFigure 12-2: SPI Serial Flash InterfaceDCSWHLDQ16MbitM25P16SISCKCSWPRSTSO16MbitAT45DB161DSPI_SCKSPI_MOSISPI_MISOSPI_SS_BALT_SS_BST_SPI_WPDATAFLASH_WPDATAFLASH_RSTROM-CS0CSO-BCSO-SELROM-CS1SPI Flash SelectJumpers (J1)10Ω 10Ω‘1’FPGA= 4.7kΩ to 3.3V(AA20)(AB14)(AB20)(C14)(C15)(C13)(Y5)(Y4)UG334_c12_02_052407Table 12-1: SPI Flash PROM Interface SignalsSignal FPGAPin Direction DescriptionSPI_MISO AB20 FPGAÅPROM Serial data: Master Input, Slave OutputSPI_MOSI AB14 FPGAÆPROM Serial data: Master Output, Slave InputSPI_SCK AA20 FPGAÆPROM Clock. Actively toggles during configuration. User I/O pin afterconfiguration.SPI_SS_B Y4 FPGAÆPROM Asynchronous, active-Low slave select signal. Actively drives Low duringSPI Flash configuration mode. User I/O pin after configuration. Drive Highif unused. Steered to selected “SPI Flash PROM Select Jumpers (J1),” page93.ALT_SS_B Y5 FPGAÆPROM Second, asynchronous, active-Low slave select signal. Pulled High duringconfiguration. User I/O pin after configuration. Drive High if unused.Steered to selected “SPI Flash PROM Select Jumpers (J1),” page 93.DATAFLASH_WP C14 FPGAÆPROM Write-protect input to Atmel AT45DB161D PROM. Must be High toprogram the PROM. Has external 4.7kΩ pull-up resistor.DATAFLASH_RST C15 FPGAÆPROM Reset input to Atmel AT45DB161D PROM. Must be High to read, program,or erase the PROM. Has external 4.7kΩ pull-up resistor.ST_SPI_WP C13 FPGAÆPROM Write-protect input to ST M25P16 PROM. Must be High to program thePROM. Has external 4.7kΩ pull-up resistor.
