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6.6 Interrupt of Extended Intelligent I/O Service (EI2OS)
6.6
Interrupt of Extended Intelligent I/O Service (EI2OS)
The extended intelligent I/O service (El2OS) automatically transfers data between a
peripheral function (resource) and memory. When the data transfer terminates, a
hardware interrupt is generated.
s Extended Intelligent I/O Service (EI2OS)
The extended intelligent I/O service (EI2OS) is a type of hardware interrupt. EI2OS transfers
data between a peripheral function (resource) and memory. The user should create program to
activate and terminate EI2OS but need not create a data transfer program.
r Advantages of extended intelligent I/O service (EI2OS)
Compared to data transfer performed by the interrupt processing routine, EI2OS has the
following advantages.
Coding a transfer program is not necessary, reducing program size.
Since transfer can be activated due to an interrupt cause of a peripheral function (resource),
there is no need of polling for a data transfer cause.
Incrementing of a transfer address can be selected.
Incrementing or no update can be selected for the I/O register address.
r Extended intelligent I/O service (EI2OS) termination interrupt
The processing branches to the interrupt processing routine when data transfer by EI2OS
terminates.
An interrupt processing program can determine the EI2OS termination cause by checking the
EI2OS status bits (S1 and S0) of the interrupt control register (ICR).
Interrupt numbers and interrupt vectors are permanently set for each peripheral. See Section
6.2 "Interrupt Causes and Interrupt Vectors", in CHAPTER
6 "INTERRUPTS" for more
information.
r Interrupt control register (ICR)
This register, which is located in the interrupt controller, activates EI2OS, specifies the EI2OS
channel, and displays the EI2OS termination status.