HDDD A2 v1.2 User`s Manual
Contents
1. 1 Red 5V 2 Black GND 3 Black GND 4 Yellow 12V FIG 3 Plug the other end of the short 4 lead colored power supply cable in 3 5 HD floppy drive s 4 pin power supply header Alternatively connect external ATX power supply s floppy drive lead to the 3 5 HD floppy drive s 4 pin power supply header if your Apple II cannot deliver enough power for the floppy drive After these steps your assembly should look like fig 4 Pay close attention to the red marking on the ribbon cable 6 14 2 5 Connecting to Apple IIe If your Apple IIe is using the standard disk controller card with two 2x10 headers plug the other end of the ribbon cable to the selected drive number as shown in fig 5a Pay close attention to the red marking on the ribbon cable F If your Apple IIe has DB19 connector at it s rear panel plug the other end of the ribbon cable to it as shown in fig 5b Please note that HDDD A2 doesn t allow connecting a daisy chained drive after itself as it lacks a pass through port 7 14 2 6 Connecting to Apple IIc IIc Find the DB19 disk port on the rear panel fig 6a and connect the other end of the ribbon cable to it as shown in fig 6b FIG 6a 8 14 FIG 6b 2 7 Connecting to Apple IIgs Find the DB19 disk port on the rear panel fig 7a and connect the other end of the ribbon cable to it as shown in fig 7b FIG 7a 9 14 10 14 3 Usage 3 1 Side s2. HDDD A2 vl 2 User s Manual 2009 bz 1 14 Contacts Product updates and general information http www bootzero com support support bootzero com Sales sales bootzero com Revision History 2009 09 05 v1 0 initial creation 2 14 1 Introduction 1 1 About HDDD A2 HDDD A2 is a modern product for the Apple II family of computers While the Apple II computers haven t lost their charm even after few decades their 5 25 drives and diskettes are beginning to show the signs of age and wear and getting scarce HDDD A2 tries to fill this gap and still keep the retro feeling by making a standard IBM PC 3a HD floppy drive and 3 5 HD diskettes a direct replacement of the venerable Disk drive 5s 1 2 Features mimicking of Disk drive user selectable side 80 tracks per side 140 KB per side compatible with DOS 3 3 ProDOS UCSD CP M up to 320 KB per side no software supplied 1 3 System Requirements Apple II computer with Disk controller card ina slot or integrated disk port 3 5 HD diskettes Please note that HDDD A2 board doesn t support neither DD drives nor 3 5 DD diskettes 3 14 2 Installation 2 1 Caution Please be sure to turn off your Apple II system before making any changes to the hardware or connections Attempt to connect or disconnect components while system is powered will likely lead to damage Please chec
3. election Disk supports only single side and there is no electrical signal or notion for side selection so this has to be selected manually HDDD A2 provides 3way header JPl with jumper for side selection Two LEDs on the board indicate currently selected side Please do not change side while write operation is in progress as this may result in data loss For increased flexibility you may install external switch and indication at a convenient place 3 2 Software There is nothing special to do to use HDDD A2 in place of Disk After successful installation you can start using 3 5 HD diskettes the same way as the old 5 25 DD ones format and copy using your favourite software and enjoy Please keep in mind that 3 5 diskettes cannot be flipped upside down use the side selection jumper to achieve this 11 14 4 For Advanced Users 4 1 Conversion The original Disk is a double density DD 300 RPM device Double density corresponds to 250 kbit sec transfer rate Apple II computers use a form of Group Code Recording GCR encoding invented by Steve Wozniak and their diskettes are incompatible with other platforms 3 5 high density HD drives work also at 300 RPM but at increased transfer rate 500 kbit sec Of course the increased capacity per track cannot be used and at the same time still be compatible with Apple II disk controllers and software so HDDD A2 employs additional FM encoding on top of t
4. he Apple s GCR to satisfy magnetic media requirements HDDD A2 also does the necessary signal conversions between Apple II and IBM PC compatibles floppy drives Each half track of Disk 1S mapped to a separate track on the 3 5 HD diskette Thus any standard Apple II operating system such as DOS 3 3 ProDOS CP M and UCSD will actually use only every other track on the 3 5 HD diskette 4 2 Extras While half of each track is sacrificed in the name of compatibility there is still benefit increased number of tracks There are 80 of them on each side leading to theoretical capacity of 320 KB per side assuming standard 16 sector format 4 3 Enhancements For users who need to switch sides often we recommend connecting an external single pole double throw SPDT 12 14 switch to JP1 header and mounting it at a convenient place 4 4 Deviations from Disk Because the drive the media and the signal encoding are different there are minor observed differences 4 4 1 There are no quarter tracks with HDDD A2 They are mapped to the nearby half track depending on head movement direction Software trying to utilise them will likely fail 4 4 2 3 5 HD drive s speed is fixed internally at 300 RPM while Disk is usually calibrated at a slightly lower speed for optimum performance The following effects may be noticed only on 14 25 MHz PAL Apple II machines as the track capacity shortens slightly d
5. k very carefully the markings on the ribbon cable connecting HDDD A2 and your Apple II computer before applying power to the system to avoid irreversible damage 2 2 General connection scheme HDDD A2 board has the following connectors Fl 34way socket to 3 5 HD floppy drive AP1 20way header to Apple II Jl 4way power header to 3 5 HD floppy drive power supply JP1 3way header jumper for side selection To Apple Il JP1 Side selection J1 To 3 5 HD floppy drive power connector To IBM PC compatible 3 5 HD floppy drive FIG 1 4 14 FIG 2 1 2 3 Connecting the cables to HDDD A2 To avoid excess force applied to the HDDD A2 board while already attached to the 3 5 HD floppy drive we recommend that first the cables are installed Plug your selected ribbon cable IDC 20 or DB19 depending on your Apple II model in APl Plug the short 4 lead colored power supply cable in Jl Alternatively skip this step and leave Jl empty if you plan to power the 3 5 HD floppy drive from external ATX power supply 2 4 Attaching HDDD A2 to 3 5 HD floppy drive Attach the HDDD A2 board s Fl socket to the 34way header at the rear side of the 3 5 HD floppy drive matching pin numbers Consult fig 3 for general diagram of a 3 5 HD drive Usually pin 3 is keyed For the majority of the drives the HDDD A2 board will face components up 5 14 3 5 IBM PC compatible Floppy Drive 1 44MB rear side
6. ue to higher RPM 4 4 2 1 Locksmith 6 0 16 sector Format Effect Tracks are reported to fail but in reality they have been formatted fine Reason Locksmith 6 0 16 sector Format reports error during post format check and a certain gap size falls below set threshold Workarounds Ignore the errors Use a different formatting program Detune the 3 5 HD floppy drive oscillator for very advanced users 4 4 3 Due to different timings track seek RPM etc some software may exhibit unusual behaviour 4 4 3 1 DOS 3 3 may slow down under some read write patterns Fast DOS versions as well as ProDOS 13 14 are not affected 4 4 4 Last but not least even if these differences especially the lack of quarter tracks may affect some complex copy protected titles for the majority it should be possible to be transferred to 3 5 HD diskettes by HDDD A2 for backup or everyday usage 14 14
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