Extended Intelligent I/O Service (Ei2Os); Overview; Figure 7.6.1A Outline Of Extended Intelligent I/O Service - Fujitsu F2MC-16LX MB90580 Series Hardware Manual

7.6 Extended intelligent I/O service (EI2OS)

7.6 Extended intelligent I/O service (EI

7.6.1 Overview

2
EI OS is a type of hardware interrupt operation that automatically transfers data between I/O and memory.
Conventionally, data is transferred between I/O and memory by an interrupt processing program. EI
however, enables data to be transferred as if in DMA mode. EI
conventional interrupt processing method:
Writing a transfer program is unnecessary, thus the entire program size can be small.
No internal register is used for transfer. Therefore, saving the register values is unnecessary,
resulting in a higher transfer speed.
I/O can stop transfer at any time. Therefore, unnecessary data is not transferred.
The buffer address can be incremented, decremented, or left unupdated.
The I/O address can be incremented, decremented, or left unupdated (when the buffer address is
updated).
At the end of EI
setting the end condition. Therefore, the user can identify the end condition type.
Figure 7.6.1a outlines the EI
CPU
Note: Notes:The area that can be specified by IOA is between 000000
The area that can be specified by BAP is between 000000
The maximum transfer count that can be specified by DCT is 65,536.
90 Chapter 7: Interrupt
2
OS processing, the CPU automatically branches to the interrupt processing routine after
2
OS.
Memory space
by IOA
I/O register
by BAP
Buffer

Figure 7.6.1a Outline of extended intelligent I/O service

2
OS)
••• ••• ••• ••• •••
by ICS
ISD
Interrupt control register
I/O requests transfer.
The interrupt controller selects the
descriptor.
The transfer source and destination
by
are read from the descriptor.
DCT
Data is transferred between I/O and
memory.
2
OS has the following advantages over the
Peripheral
I/O register
Interrupt request
Interrupt controller
and 00FFFF
H H
and FFFFFF .
H H
2
OS,
.
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