Configuration Handbook - Kamami.pl

Passive Parallel Asynchronous ConfigurationFigure 6–27. APEX II PPA Configuration Timing Waveformt CFGt STATUSnCONFIGnSTATUS (1)CONF_DONE (2)DATA[7..0]t CF2ST1t DSUt CSSUt CSHt CD2UMByte 0 Byte 1Byte n 1Byte n(4)(3) CS(3) nCSnWSRDYnBSY(4)t t CF2WSDH(4)t WSP(4)t RDY2WS(4)t WS2Bt BUSYt CF2ST0t CF2CDUser I/OsHigh-ZHigh-ZUser-ModeINIT_DONENotes to Figure 6–27:(1) Upon power-up, the APEX II device holds nSTATUS low for not more than 5 μs after V CCINT reaches its minimumrequirement.(2) Upon power-up, before and during configuration, CONF_DONE is low.(3) The user can toggle nCS or CS during configuration if the design meets the specification for t CSSU , t WSP , and t CSH .(4) DATA0 should not be left floating after configuration. It should be driven high or low, whichever is more convenient.DATA[7..1], CS, nCS, nWS, nRS and RDYnBSY are available as user I/O pins after configuration and the state oftheses pins depends on the dual-purpose pin settings.Figure 6–28 shows the timing waveform for the PPA configurationscheme when using a strobed nRS and nWS signal.6–54 Altera CorporationConfiguration Handbook, Volume 1 August 2005