LC87FBK08A

No.A1956-3/28

Interrupts

• 15 sources, 9 vector addresses

1) Provides three levels (low (L), high (H), and highest (X)) of multiplex interrupt control. Any interrupt requests of

the level equal to or lower than the current interrupt are not accepted.

2) When interrupt requests to two or more vector addresses occur at the same time, the interrupt of the highest level

takes precedence over the other interrupts. For interrupts of the same level, the interrupt into the smallest vector

address takes precedence.

No.

Vector Address

Level

Interrupt Source

1

00003H

X or L

INT0

2

0000BH

X or L

INT1

3

00013H

H or L

INT2/T0L/INT4

4

0001BH

H or L

INT3/base timer

5

00023H

H or L

T0H

6

0002BH

H or L

T1L/T1H

7

00033H

H or L

None

8

0003BH

H or L

SIO1

9

00043H

H or L

ADC/T6/T7

10

0004BH

H or L

Port 0

• Priority levels X > H > L

• Of interrupts of the same level, the one with the smallest vector address takes precedence.

Subroutine Stack Levels: 128levels (The stack is allocated in RAM.)

High-speed Multiplication/Division Instructions

• 16 bits × 8 bits

(5 tCYC execution time)

• 24 bits × 16 bits

(12 tCYC execution time)

• 16 bits ÷ 8 bits

(8 tCYC execution time)

• 24 bits ÷ 16 bits

(12 tCYC execution time)

Oscillation Circuits

• Internal oscillation circuits

Low-speed RC oscillation circuit (SRC):

For system clock / For Watchdog timer (100kHz)

Medium-speed RC oscillation circuit (RC):

For system clock (1MHz)

Frequency variable RC oscillation circuit (MRC): For system clock (8MHz

±2.5%, Ta=-10°C to +85°C)

• External oscillation circuits

Hi-speed CF oscillation circuit (CF):

For system clock, with internal Rf

Low speed crystal oscillation circuit (X’tal):

For low-speed system clock / For Watchdog timer,

with internal Rf

1) The CF and crystal oscillation circuits share the same pins. The active circuit is selected under program control.

2) Both the CF and crystal oscillator circuits stop operation on a system reset. After reset is released, oscillation

is stopped so start the oscillation operation by program.

System Clock Divider Function

• Can run on low current.

• The minimum instruction cycle selectable from 300ns, 600ns, 1.2μs, 2.4μs, 4.8μs, 9.6μs, 19.2μs, 38.4μs, and

76.8

μs (at a main clock rate of 10MHz).

Internal Reset Function

• Power-on reset (POR) function

1) POR reset is generated only at power-on time.

2) The POR release level can be selected from 4 levels (2.57V, 2.87V, 3.86V, and 4.35V) through option

configuration.

• Low-voltage detection reset (LVD) function

1) LVD and POR functions are combined to generate resets when power is turned on and when power voltage falls

below a certain level.

2) The use or disuse of the LVD function and the low voltage threshold level (3 levels: 2.81V, 3.79V, 4.28V) can be

selected by optional configuration.