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PXA3xx Design Guide - Marvell

PXA3xx Design Guide - Marvell

PXA3xx Design Guide - Marvell

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To prevent erroneous nPCE assertions during reset, the board must have board-level 4.7 KΩpull-ups.Refer to the <strong>Marvell</strong> ® PXA32x Processor Electrical, Mechanical, and Thermal Specification foradditional information. The weak (50 KΩ nominal) on-chip pull-downs are released when the RDHbit is cleared. Subsequently, contentions through the two board-level pull-ups occur only duringPC-card accesses.External Logic for PC-Card Implementation Block DiagramSee Figure 37 for illustration of the minimal glue logic needed for a PC-card system. The illustrationshows:• Data transceivers• Address buffersFigure 37 does not show all level-shifting buffers that may be required to interface between thePC-Card and the DFI interface.The transceivers are enabled by the PSKTSEL signal. The DIR pin of the transceiver is driven by theRDnWR pin. A GPIO is used for the three-state signal of the address and nPWE lines. These signalsmust be three-stated because they are used for memories other than the card interface. The CardDetect signals are driven by the single device.Figure 37: PC-Card Block Diagram - Operation in AA/D Muxed ModenXCVRENData Flash Interface (DFI)DF_IOnLUAnLLAnIOIS16, nPWAITLatchLatchDF_CLE_nOE, DF_ALE_WExnPIOR, nPIOWGPIOz 4 , GPIOa 4GPIOb 4GPIOc 4XCVRDRDnWR 7nPCE1 5 , nPCE2 5 , nPREG 5A 6AnIOIS16, WAIT#OE#, WE#nIOR, nIOWCD1#, CD2#ReadyWPPC-CardRequired >=10 KΩ 10KΗpullup notshown forWAIT#, CD1#,CD2#,READY,11.5.4.2 PC Card Layout NotesPull-up resisters shown in Figure 37 must be 10 KΩ or greater in value. Refer to <strong>Marvell</strong> ® PXA30x,PXA31x, and PXA32x Processor Electrical, Mechanical, and Thermal Specification timinginformation.Copyright © 2009 <strong>Marvell</strong>Doc. No. MV-S301368-00 Rev. AApril 6, 2009, Released Page 91

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