IBM System/7 Functional Characteristics - All about the IBM 1130 ...

111.1111 111111 N uData and control characters are transmitted one byte at a time. On output, bits 8 to15 of the index register or accumulator are sent to the ACCA and bits 9 to 15 are transmittedover the communications line. Register bit 8 indicates to the ACCA if the characteris uppercase or lowercase. Bit 8 is set to 1 if the character is uppercase; bit 8 is set to0 if it is lowercase. The System/7 program does not need to insert an upshift or downshiftcharacter. The ACCA transmits an upshift character if bit 8=1 or a downshift characterif bit 8=0 prior to transmitting the character contained in bits 9 to 15 of the register.On input, received data replaces the contents of bits 9 to 15 of the index register oraccumulator. The ACCA sets bit 8 on when an upshift character is received. This bitsignifies uppercase and will remain on for all subsequent characters until a DS, EOB, orEOT character is received. Bits 0 to 7 are set to 0 if the ACCA is not operating in binarydata mode. (Binary data mode is explained later in this chapter.) If the ACCA is operatingin binary data mode, received data replaces the contents of bits 0 to 15 of the index registeror accumulator.Interruption requests are made to the System/7 processor only if the host attachmentswitch on the System/7 console is in the enable or enable and IPL position. If the switchis in the disable position, condition code 3 is returned to the processor whenever theACCA is addressed.Transmit Control0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 * . * 0 0 1 0 0 0 0 0 1 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0'ill ii 11 1111 III 11111 11111•■••■■•••••0 8 2 0 9 3 0 0This command puts the ACCA into transmit status. The R field is ignored. If theACCA is in receive status or receive mode, it returns condition code 1 to the processorand sets bit 4 (ACCA check) in the direct control channel status word.The ACCA attempts to establish a data link with the remote processor, during whichtime the ACCA remains busy. A time limit of 16.5 seconds is allowed to establish thedata link and to issue a transmit character command. If the data link is established, theACCA presents an interruption request after setting the ready-to-transmit bit (bit 6) inthe ISW. If no link is established, a time-out interruption request (ISW bit 5 is set) ispresented, instead of the ready-to-transmit interruption request.Transmit Character0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 XXX 0010000000010011000000001111 Ii II 1111 111 1 1 1 1 1 1 1 1 1 I....11•Ne.M.,•••■■\,,••■• "aft./ ••••■••■,....110,0 8-F 2 0 1 3 0 0This command transfers bits 8 to 15 of the index register (R), or the accumulator ifR=000, to the ACCA. If the ACCA is in receive status or receive mode, it returns conditioncode 1 to the processor and sets bit 4 (ACCA check) in the direct control channelstatus word. When character transmission begins, the ACCA presents an interruption requestafter setting the ready-to-transmit bit (bit 6) in the ISW.For a multiple-character transmission, a single transmit control command should precedethe transmit character command(s) in order to establish the data link and place theACCA in transmit status. The first EOA character transmitted places the ACCA in transmitmode.pip 1191AUliipgip ! !III !IF! lllR111 41111!!!!!!!!!!!!!!!!PIP!!!!!!I!!!!!!!77-