Figures 8-7, 8-8 and 8-9 show the timing parameters of the Amiga's floppy disk subsystem with a Chinon drive. Keep in mind that this information can change with floppy drives from other vendors. To ensure compatibility with future versions of the system, you should avoid using this information in applications. 500ms min |<--------->| __ | MOTOR | | ON |___________________________________________________________ __ | ________ DRIVE | | | SELECT |__________________________________________________| | | 1.2ms min | | | |<--------------->| _____ ___________________________________ ______________ STEP | | | | | |__| | | |__| | | | | -->| |<--18ms min | 1.3ms min | -->| |<--1us min |<--------->| ______________ __________________________ WRITE | | GATE |____________________| 1.2ms min -->| |<--1000us min |<---------->| ___________ | (see text) | _____________ SIDE | | | | SELECT |____________________________________| 8us max-->| |<-- -->| |<--8us max ______________________________________________________________ WRITE | | | | | | DATA | |__|__|__|__|__| | Figure 8-7: Chinon Write Timing Diagram ____ _______ DRIVE | | SELECT |_________________________________________________| | | | | 3ms | | | | t | 18 ms min | | min | 18 ms min | | |<---->|<---------->| |<---->|<---------->| |<-t ________ _________ ___ ___ _________ __________ STEP | | | | | | | | | | |__| |__| |__| |__| |__| | t | t | t | | | | t | t | |<--->|<--->|<---->| ->| |<-t |<--->|<---->| ___________ | _________________ DIRECTION | | | | SELECT _____| | |__________________________| | 4ms | max | | | |<---->| ->| |<-t __________________ __________________________________ | | TRACK 00 |________| Figure 8-8: Chinon Access Timing Diagram __ DRIVE | SELECT |___________________________________________________________ -->| |<--1us min _____ _____________________________________________________ STEP | | | |__| | 18ms min | |<------------->| | | 1us min | |<------------------->| ________________________ _____________________________ WRITE | | GATE | | |_______| | | 1000us min | 1.2ms min | | (see text)->| |<-- |<------------>| ______________________ | | ______________ SIDE | | | SELECT | -->| |<--18ms |________________________| | | | max |1us min | | | | | 1000us min |<------>| 1.2ms max-->| |<-- -->| |<-(see text) ______________________________________________________________ VALID | | | | | | | | | | | | | | READ DATA |__|__|__| |__|__|__|__| |__|__|__|__| Figure 8-8: Chinon Read Timing Diagram CIAAPRA/CIABPRB - Disk selection, control and sensing Disk DMA Channel Control DSKPTH - Pointer to Data DSKLEN - Length, Direction, DMA Enable DSKBYTR - Disk Data Byte and Status Read (read-only) ADKCON and ADKCONR - Audio and Disk Control Register DSKSYNC - Disk Input Synchronizer
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