Browse Prior Art Database

Bit Timer for Data Read and Write Operations

IP.com Disclosure Number: IPCOM000048226D
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Compton, JI: AUTHOR [+2]

Abstract

A timing circuit coordinates date read and write operations for a magnetic storage using a small number of standard electronic parts.

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Bit Timer for Data Read and Write Operations

A timing circuit coordinates date read and write operations for a magnetic storage using a small number of standard electronic parts.

Referring to the figure, a counter 10 receives a high frequency signal (e.g., 2 MHz) from e system clock (not shown) and acts as a divider to reduce the signal frequency (producing signal CLK') to a level where, for example, sixteen pulses correspond to the longest intended storage operation. The signal CLK' is processed by an inverter 12 and is supplied to a selectively initialized counter 14 that receives count values from a controller, such as a microprocessor (referenced as micron p but not shown). The count values correspond to the storage operation to be performed (see table). An output signal BOR is taken from the inverted "Borrow" terminal of the counter 14 and is supplied to the clock (CLK) input terminals of flip-flop circuits 16 and 18.

To write data to the storage (not shown), the signal line from the Q terminal of the flip-flop 18 is switched to supply a flux direction command signal FDIR to the storage "write" circuitry. The FDIR signal changes state at the end of each count period as indicated by the signal BOR. Toggle action of the flip-flop 18 results from the connection of the terminal Q to the terminal D.

As indicated in the table, a short period between flux reversals preferably corresponds to a logic one end a long period corresponds to a logic zero. The BOR signal also acts on the flip-flop 16 to cause a pulse to be applied to the LD terminal of the counter 14 to cause initialization with t...