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Microprogram Control for Tapeless Carriage Printers

IP.com Disclosure Number: IPCOM000074746D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 5 page(s) / 150K

Publishing Venue

IBM

Related People

Frassetto, HE: AUTHOR [+2]

Abstract

1) Program to Check Validity of Carriage Buffer Data. The Carriage Buffer Load routine (CCBL) is responsible for checking that the data transferred to the Carriage Control Buffer is valid. The routine is entered from the Polling Routine (BSWI) after the channel has completed loading the forms image in the buffer and before Ending Status is presented to the channel. Any error encountered by the routine will set "Unit Check" status, and "Load Check" bit in sense byte zero. The request for this routine is set by hardware. The routine operates in Channel Mode and Zone 7.

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Microprogram Control for Tapeless Carriage Printers

1) Program to Check Validity of Carriage Buffer Data.

The Carriage Buffer Load routine (CCBL) is responsible for checking that the data transferred to the Carriage Control Buffer is valid. The routine is entered from the Polling Routine (BSWI) after the channel has completed loading the forms image in the buffer and before Ending Status is presented to the channel. Any error encountered by the routine will set "Unit Check" status, and "Load Check" bit in sense byte zero. The request for this routine is set by hardware. The routine operates in Channel Mode and Zone 7.

The following functions will be performed by "CCBL" as shown in Fig. 1: 1 Check for Channel 1 in the first position of the buffer. No Channel 1 in first position will be considered an error. 2 Check for the "Flag" bit in the last position loaded. No "Flag" in last position will be considered an error. 3 Check for a "Fold" bit between Channel 1 and the "Flag." Absence of the "Fold" bit will be considered an error. 4 Multiple "Flags" or "Fold" bits will be considered an error. 5 Generate the number of emitter pulses from the "Fold" bit to the "Flag" bit. 6 Generate the total number of emitter pulses in the buffer. 7 Determine whether the length of the buffer in pulses is a valid paper length. 8 Check the validity of the bit combinations for all positions. 9 Generate the total line count for the page. 11 Initialize the Carriage Emitter Counter (CEP) to zero. 12 Set the Ending Status. 13 Reset the CCB request latch. The layout of the Carriage Buffer data byte follows: Bit 0 1 2 3 4 5 6 7 Use 0 S X F 8 4 2 1 Bit 0 - Not Used. Bit 1 - S Bit - Used to denote the number of emitter pulses to the next line. S=0, 6 lines/inch - 8 pulses S=1, 8 lines/inch - 6 pulses Bit 2 - X Bit (Fold) - Denotes the last printable position on the page, before the perforation. Bit 3 - F Bit (Flag) - Locates the last position of the present buffer load. Bits 4, 5, 6, 7 - Used in combination to signify the Channels 1 thru 12. Combinations 13, 14 and 15 are invalid.

The following locations in Auxiliary Storage, module 0 are reserved: (1) Locations 0010, 0011 -- Emitter pulse count from the "Fold" to the "Flag." (2) Locations 0012, 0013 -- Total emitter pulse county for the form (TCEP). (3) Location 0028 -- Total line count for the form.

This routine starts checking the buffer from the last loaded position through to the first position. The address of the last position is determined from the channel address register (Register P) in Zone 1. 2) Carriage Initial Lookahead Program.

The Carriage Initial Lookahead program will have the responsibility to determine the ultimate distance that the carriage will have to move in order to execute the desired carriage movement.

The program is entered, as shown in Fig. 2, through a combination of the "Carriage Request" signal being on and "Initial Lookahead" status being set. The movement required is determined fr...