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

Read Digital Input Reference RegisterO 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 001 XX O 1000000001000 OX 0 OXXXXXX1 11 Ii II 1111 III 11111 III 11O 8-F 4 0 2 0 or 1 0-3 XThis command stores the contents of the 16-bit reference register associated with group 0or group 1. The choice is determined by the device address field in the command: 000000for group 0 or 000100 for group 1.The reference register contents are stored into the index register (R), or the accumulatorif R=000.The reference registers are part of the Process Interrupt feature for groups 0 and 1, andare used for comparison with the 16-point group input register. Interruption requests canbe presented for either an equal or an unequal comparison; the choice is under controlof the program. (Refer to "Set Digital Input Interrupt Control" later in this chapter.)Set'Digital Input Latch ControlO 5 8 11 16 20 26 31Op code0 0 0 0 1 X X XFun0 0 11 IZeros0 0 0 0 0Mod0 0 0 0I I IDA0 X X X 0 0I I 1 I 1MAXXXXXX11111O8-F 2 0 0 0-7 0-3 XThis command sends control information to the digital input group identified by thedevice address field. The control information is indicated by the value of bit 15 of the indexregister (R), or the accumulator if R=000, and has the following format:0 15Not UsedI 1 I I 1 I I I 1 I 1 I I IO 0 0 0 or 1Control information in bit 15 can be directed to any of the eight possible digital inputgroups (groups 0 to 7) in a multifunction module. The setting of bit 15 determines whetherthe selected group is to operate in the latched or unlatched mode. Bit 15 set to a 1 valuespecifies the latched mode, and a 0 value specifies the unlatched mode.When the Process Interrupt feature is installed, changing modes (latched to unlatchedor unlatched to latched) resets the digital input register to the all 0's state. The registerwill remain all 0's until the next positive transition of the user's input signal (logical 0 to 1).Setting bit 15=0 also resets the digital input register to the all 0's state.Note. If while in the latched mode of operation, the user's signal has remained in thelogical 1 state when unlatched mode of operation is selected, the group must be reinitiatedbefore normal unlatched mode operation takes place. Either of two methods can be usedto restore the digital input register to again reflect the user's input values.1. Program the following sequence:—Issue a set-test-signal command (bit 15=0).—Establish a 3-microsecond delay.—Issue a read/reset-digital-input-register command.2. Ensure that the user's input value returns to a logical 0 after the completion oflatched mode operation.