four-cycle handshake

four-cyclehandshake© 2000 MorganKaufmanOverheads for Computers asComponents© 2000 MorganKaufmanOverheads for Computers asComponents

© 2000 MorganKaufmanOverheads for Computers asComponents© 2000 MorganKaufmanOverheads for Computers asComponents

urst read© 2000 MorganKaufmanOverheads for Computers asComponentsaddress/data multiplexing© 2000 MorganKaufmanOverheads for Computers asComponents

DMA© 2000 MorganKaufmanOverheads for Computers asComponentsattività del sistema duranteun trasferimento in DMA© 2000 MorganKaufmanOverheads for Computers asComponents

limitazione del tempo diattività del DMA© 2000 MorganKaufmanOverheads for Computers asComponents© 2000 MorganKaufmanOverheads for Computers asComponents

MemoriaSRAM, DRAM, ROMSRAM più veloce che DRAMSRAM consuma di più che DRAMLe DRAM sono più denseLe DRAM richiedono rinfresco© 2000 MorganKaufmanOverheads for Computers asComponentsSRAM© 2000 MorganKaufmanOverheads for Computers asComponents

DRAMrefresh: CAS-before-RAS© 2000 MorganKaufmanOverheads for Computers asComponentspage mode© 2000 MorganKaufmanOverheads for Computers asComponents

DRAM sincrona© 2000 MorganKaufmanOverheads for Computers asComponentsorganizzazione di memoriamultichip© 2000 MorganKaufmanOverheads for Computers asComponents

infresco© 2000 MorganKaufmanOverheads for Computers asComponentsI/O devicesI/O devices:serial linkstimers and counterskeyboardsdisplaysanalog I/O© 2000 MorganKaufmanOverheads for Computers asComponents

Timers and countersVery similar:a timer is incremented by a periodic signal;a counter is incremented by anasynchronous, occasional signal.Rollover causes interrupt.© 2000 MorganKaufmanOverheads for Computers asComponentsWatchdog timerWatchdog timer is periodically reset bysystem timer.If watchdog is not reset, it generates aninterrupt to reset the host.host CPUinterruptresetwatchdogtimer© 2000 MorganKaufmanOverheads for Computers asComponents

Digital-to-analogconversionUse resistor tree:b nb n-1R2RV outb n-2b n-34R8R© 2000 MorganKaufmanOverheads for Computers asComponentsFlash A/D conversionN-bit result requires 2 n comparators:V in...encoder© 2000 MorganKaufmanOverheads for Computers asComponents

Dual-slope conversionUse counter to time required tocharge/discharge capacitor.Charging, then discharging eliminatesnon-linearities.V intimer© 2000 MorganKaufmanOverheads for Computers asComponentsSample-and-holdRequired in any A/D:V inconverter© 2000 MorganKaufmanOverheads for Computers asComponents

glue logic© 2000 MorganKaufmanOverheads for Computers asComponents