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

I II III• 1111111111111111 1•111111111111111■NIIIIIIIMMommilEllii■iiiimmommi !min immlDiagnostic WriteO 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 XX OO10000000000011000000001111 II 11 1111 111 11111 11 111••••■•■•■,••■••O 8-F 2 0 0 3 0 0This command supplies bit 8 of the index register, or accumulator if R=000, to the outputof the transmit circuits. The output must be manually connected to the ACCA input fortesting of the receive circuits.Nine diagnostic write commands are needed to create a character in the ACCA beforean interruption request can be presented to the processor. Bit 8 of the index register oraccumulator determines the setting of the bit transmitted by the ACCA. If bit 15 of theindex register or accumulator is set to 1, the ACCA exits from diagnostic mode. Each ofthe nine diagnostic write commands represents one of the nine bit-times required totransmit a character—start, 7 character bits, and stop. The following chart gives the settingsof bits 8 and 15 for transmitting a character with diagnostic write commands.Command No.12-89LastRead ISWName R-Reg ContentsStart Bit 8 =0; bit 15=0Character bits Bit 8=x; bit 15=0Stop Bit 8=1; bit 15=0Exit diagnostic mode Bit 8=x; bit 15=1O 58 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 X X X 0 1 0 0 0 0 0 0 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 01111 II 11 1111 III 11111 1 1111•••■•••••,••■•• ....1111.,./.11•■•••••••■,,••••••• S.~O 8-F 4 0 3 3 0 0This command stores the 16-bit interrupt status word (ISW) associated with the ACCAinto the index register (R), or the accumulator if R=000.Interrupt Status Word (ISW): Bits in the interrupt status word are set on to indicate theoperating status of the ACCA and to notify the system of errors detected. Interruptionsresult from setting on any ISW bits except 1, 8, 10, and 12. When the interruption requestis serviced by the program, subsequent execution of any command to the ACCA resets theISW. The ISW is also reset by system reset.Descriptions of significant bits in the ACCA ISW follow. An asterisk (*) next to the bitnumber indicates that the summary status indicator is also set when the resulting interruptionrequest is presented to the processor. If the asterisk is enclosed in parentheses,the summary status indicator is set only when a specific condition sets the ISW bit.