Epson PC AX Technical Manual page 241

REV.A
DIAGRAMS ARD REFERENCE MATERIALS
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I
FLOPPY DISK DRIVE(S) AND CONTROLLER CHECK
Error code
=
605
READ ERROR
TRACK -- xx
SECTOR - Y
SIDE ---
z
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(xx represents the error cylinder number, y represents the error
sector number, and z represents the error head number.)
4) Speed Check
The drive is selected as in Item 1). The speed check performs
60 times one-sector reading operationsof Sector 1 of Cylinder
No.32, Head No. 0, and the program measuresthe time for this
operation using the Channel 0 of 8254.
Measurement is performed by counting the 8254 interrupt, which
occurs every 1/18 second, and correcting by adding the number of
the final Timer Count value. Finally the program displays the
revolution speed in rpm (revolution per minutes).
expression:
(60 [times])/(interrupt count)*(18 [sec/times])*(60 [sec])
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The disk rotation speed should be more than xxx.x rpm and
less than yyy.y rpm
The disk rotation speed is now zzz.z rpm
Press any key to return to the menu
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(xxx.x represents the lower-limit revolution value, yyy.y represents
the upper-limit revolution value, and zzz.z represents the current
revolution value.)
The lower-limit revolution value is 294.0 for 360 KB drive and
720 KB (3.5"), 352.8 for 1.2 MB. (Normal revolution value - 2%.)
And the upper-limit revolution value is 306.0 for 360 KB drive and
720 KB (3.5"), 367.2 for 1.2 MB. (Normal revolution value
+
2%.)
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