Chapter 6. Service Request Function326 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C6.28 SVC_REQ 32: Suspend/Resume I/O InterruptUse SVC_REQ 32 to suspend a set of I/O interrupts and cause occurrences of these interrupts to bequeued until these interrupts are resumed. The number of I/O interrupts that can be queueddepends on the I/O module’s capabilities. The CPU informs the I/O module that its interrupts are tobe suspended or resumed. The I/O module’s default is resumed. The Suspend applies to all I/Ointerrupts associated with the I/O module. Interrupts are suspended and resumed within a singlescan.SVC_REQ 32 uses only an input parameter block. Its length is three words.Address 0 = resume interrupt1 = suspend interruptAddress + 1 memory typeAddress + 2 reference (offset)Successful execution occurs unless:▪ Some number other than 0 or 1 is passed in as the first parameter.▪ The memory type parameter is not 70 (%I memory).▪ The I/O module associated with the specified address is not an appropriate module for thisoperation.▪ The reference address specified is not the first %I reference for the High Speed Counter.▪ Communication between the CPU and this I/O module has failed. (The board is not present, or ithas experienced a fatal fault.)Note: I/O interrupts, unless suspended or masked, can interrupt the execution of a function block.The most often used application of this Service Request is to prevent the effects of theinterrupts for diagnostic or other purposes.SVC_REQ 32 ExampleInterrupts from the high speed countermodule whose starting point referenceaddress is %I00065 will be suspendedwhile the CPU solves the logic of thesecond rung. Without the Suspend, aninterrupt from the HSC could occurduring execution of the third rung and%T00006 could be set while %R000001has a value other than 3,400.(%AI00001 is the first non-discrete inputreference for the High Speed Counter.)
