CHAPTER 3: CPU OPERATION

 

 

0

1

2

3

4

5

 

CLK

 

 

 

 

 

 

 

 

PK

 

 

 

 

 

 

 

 

PL

 

 

 

 

 

 

 

 

PC

pc-2

pc-1

 

pc

 

010xH

ANY

 

FETCH

ANY

ANY

DUMMY

 

(010xH)

ANY

 

BS16

 

 

 

 

 

 

 

 

DBS1/0

 

ANY

 

2

1

2

ANY

 

WR

 

 

 

 

 

 

 

 

RD

 

 

 

 

 

 

 

 

RDIV

 

 

 

 

 

 

 

 

DA00–DA15

 

ANY

 

SP2-1

DUMMY

SP1-1

 

 

D0–D3

 

 

 

F reg.

xH

 

 

 

 

 

 

 

 

Inte rrupt vector

 

 

M00–M15

 

 

 

 

 

pc

 

 

IRQ

 

 

 

 

 

 

 

 

IACK

 

 

 

 

 

 

 

 

NACK

 

 

 

 

 

 

 

 

IF

 

 

 

 

 

 

 

 

 

Interrupt sampling

Interrupt processing by the hardware

Executing the interrupt service routine

 

 

 

 

4–6 cycle

 

 

 

 

 

 

0

 

1

2

3

4

5

CLK

 

 

 

 

 

 

 

 

PK

 

 

 

 

 

 

 

 

PL

 

 

 

 

 

 

 

 

PC

pc-3

pc-2

pc-1

 

pc

 

010xH

ANY

FETCH

ANY

LDB %EXT,imm8 LD %A,[%X]

DUMMY

 

 

(010xH)

ANY

BS16

 

 

 

 

 

 

 

 

DBS1/0

 

ANY

0

3

2

1

2

ANY

WR

 

 

 

 

 

 

 

 

RD

 

 

 

 

 

 

 

 

RDIV

 

 

 

 

 

 

 

 

DA00–DA15

 

 

ANY

00xxH

SP2-1

DUMMY

SP1-1

 

D0–D3

 

 

 

[00xxH]

F reg.

xH

 

 

 

 

 

 

 

 

Inte rrupt vector

 

 

M00–M15

 

 

 

 

 

 

pc

 

IRQ

IACK

Fig. 3.5.2.3 Hardware interrupt

(IRQ) sequence (normal acceptance)

In this chart, the dummy fetch cycle starts after fetching the "LD %A, [%X]" instruction that follows the "LDB %EXT, imm8" instruction.

Fig. 3.5.2.4 Hardware interrupt

NACK

(IRQ) sequence

IF

Interrupt sampling

 

 

 

 

 

 

 

 

Interrupt processing by the hardware

Executing the interrupt service routine

 

(interrupt acceptance

after 1 instruction)

S1C63000 CORE CPU MANUAL

EPSON

29