NEC uPD372 Floppy Disk Controller Addendum Apr77 free download

File name uPD372_Floppy_Disk_Controller_Addendum_Apr77.pdf

~EC IlcrOcOlputers, Inc. }LPD372 ADDENDUM TO FLOPPY DISK CONTROLLER USERS' MANUAL FOR MINIFLOPPyTM APPLICATIONS TM - Shugart Associates Five Militia Drive/Lexington, Massachusetts 02173 Telephone (617) 862-6410 Telex 92-3434 TABLE OF CONTENTS INTRODUCTION 2 MINIFLOPPY INTERFACE SIGNALS 3 RECORDING FORMAT 6 DATA CONDITIONER 9 SAMPLE CONTROLLER DESIGN 11 Hardware 11 Software 13 1 INTRODUCTION The discussion and design shown in this Addendum is dedicated to the MinifloppyTM Diskette Storage Drive. This drive is somewhat different, both electrically and mechanically, from the standard floppy disk drives found throughout the industry. The Minifloppy is smaller, less expensive, and is based upon the same floppy disk drive technology as the standard floppy. However, its data transfer rate is half as fast and its total data storage capacity is approximately one-third. This design uses a single uPD372 Floppy Disk Controller to control a pair of Minifloppies. The interface to the floppies has been configured so as to allow overlap-seeks to be programmed. If only a single drive is used or if overlap-seeks are not required, then two or three logic Ie's may be removed from this design. The controller's architecture remains the same as in the standard floppy design shown in the uPD372 Users' Manual. Before proceeding into the design of this controller, the uPD372 Users' Manual should be read. All the basic concepts and characteristics of the uPD372 are explained in this document, and it will be assumed that the reader is familiar with them. For clarity in this document the uPD372 Users' Manual will be referred to as Users' Manual and this document referred to as the Addendum. TM -- Shugart Associates 2 MINIFLOPPY INTERFACE SIGNALS There are several signals which have been deleted in the Minifloppy as well as several new signals. These are summarized below: Deleted Signals New Signals (Used only on Standard Floppy) Head Load Index/Sector write Fault Drive Select I write Fault Reset Drive Select 2 Low Current Drive Select 3 Sector Motor ON Index Ready The Head Load signal has been deleted in the Minifloppy. The head is loaded concurrently with the Motor ON signal. write Fault a