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

Start Timer0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 ** 0 0 1 0 0 0 0 0 1 0 0 1 0 0 0 X 0 0 0 0 0 0 0 0iill ii 1 1 I I I 1 III 1 1 1 I 1 1 1 1■••■••■,,MAN.,•■••••%,..MII ••••••••■,,•■■•• s...s•••■•••=1111.,O 8 2 0 9 0 or 1 0 0The addressed timer (specified by the device address field) is started. The R field is ignored.When the timer completes counting the specified number of 50-microsecond timer intervals,an interruption request is presented to the processor.Condition code 2 is set when the start timer command is issued to a timer that has aninterruption pending, or is already on and counting.Stop Timer0 5 8 11 16 20 26 310Op code0 0 01111R**IIFun0 0 1IIZeros0 0 0 0 011 1 1Mod1 0 0 0IIIDA0 0 0 X 0 01 111 10 01 1MA0 0 01 101O 8 2 0 8 0 or 1 0 0The addressed timer (specified by the device address field) is stopped. The R field isignored. Timers must be stopped before they are set to a new value.Read Timer0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 XXX 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 XO 0 0 0 0 0 0 0iili ii II 1 1 1 I III 1 1 1 1 1 11 1 I 1••■•■•■,....."••■■••,..1••••••••••••,,,onlaso,O 8-F 4 0 8 0 or 1 0 0The count value in the addressed timer (specified by the device address field) is storedinto the index register (R), or the accumulator if R=000. No interruption occurs and thetimer continues to count.TIMER INTERRUPTIONSTimer interruption requests use the same interruption mechanism as the I/O devices. Aread-ISW command to the timers always records an interrupt status word that contains all0's because no errors can occur during timer operations and timer interruptions have onlyone meaning.When the timers request an interruption, the contents of the device address field in theinterruption identification will correspond to the proper timer (0 or 1), even though bothtimers were prepared by a single prepare I/O command.In the event of simultaneous interruptions, timer 0 has priority over timer 1.Interval Timers 6-3Frr ,11 1,171111.11T! 11 •