Browse Prior Art Database

Microprogram Single Shots

IP.com Disclosure Number: IPCOM000073900D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Frassetto, HE: AUTHOR [+2]

Abstract

The synchronous motor drive for the type chain in a printer can be used as the source of pulses to (1) drive a counter or (2) updated a software counter by an interrupt to a macrocontrol program.

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Microprogram Single Shots

The synchronous motor drive for the type chain in a printer can be used as the source of pulses to (1) drive a counter or (2) updated a software counter by an interrupt to a macrocontrol program.

The time-outs for two single shots of 12 and 16 ms previously used fur (1) determining whether the printer carriage failed to Move when signaled to do so, and (2) inhibiting operations until the Carriage Settles, were accomplished by using as a constant time base pulses from the chain driver which is driven by a synchronous motor. These pulses cause the interrupt of a microprogram at a predetermined rate. During these interrupts the required time-out is accomplished.

The request for the desired time-out is made by microprogram routines which control movement of the printer carriage. These routines decide when the time- outs are desired.

The request is initiated by setting on a software bit in a predetermined area of memory. When this time out request bit is on during a train-pulse interrupt, the microprogram will initiate a software counter with a constant value which pertains to the number of subsequent interrupts expected in the desired time-span. Each following interrupt will cause the microprogram to decrement this counter. When the counter equals zero, the required time will have elapsed and the program will set the corresponding indicator to specify the time-out.

As more I/O Control Units tend toward microprogram control, this method of pr...