HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 99

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

4.2
The SCA has nine registers for interrupt control. These registers can be accessed by read and write
instructions from the MPU.
4.2.1
The interrupt vector register stores the vector address output to the MPU in an interrupt
acknowledge cycle.
Any des i red vector addres s can be set . Vect or out put wi ll be det ail ed in sect i on 4. 3, Vect or Output .
4.2.2
The interrupt modified vector register stores a modifiable vector address output to the MPU in an
interrupt acknowledge cycle.
The register consists of eight bits. The six low-order bits hold a hardware-generated code
identifying the interrupt source. If multiple interrupt sources are active simultaneously, IMVR
holds the code of the source with the highest priority. Any desired value can be set in bits 7 and 6
(IMVR7, IMVR6).
Registers
Interrupt Vector Register (IVR)
Interrupt Modified Vector Register (IMVR)
Read/Write
Initial value
Bit name
R/W
IVR7
7
0
R/W
IVR6
6
0
IVR5
R/W
5
0
Fixed vector address
IVR4
R/W
4
0
IVR3
R/W
3
0
IVR2
R/W
2
0
Rev. 0, 07/98, page 83 of 453
R/W
IVR1 IVR0
1
0
R/W
0
0