LC87F0A08A

No.A1535-4/24

Internal Reset Circuit

Power-on reset (POR) function

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

2) The POR release level can be selected from 8 levels (1.67V, 1.97V, 2.07V, 2.37V, 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/disuse of the LVD function and the low voltage threshold level can be selected from 7 levels

(1.91V, 2.01V, 2.31V, 2.51V, 2.81V, 3.79V and 4.28V). through option configuration.

Standby Function

HALT mode: Halts instruction execution while allowing the peripheral circuits to continue operation.

1) Oscillation is not halted automatically.

2) There are three ways of resetting the HALT mode.

(1) Setting the reset pin to the low level

(2) Having the watchdog timer or LVD function generate a reset

(3) Having an interrupt generated

HOLD mode: Suspends instruction execution and the operation of the peripheral circuits.

1) The CF, RC and crystal oscillators automatically stop operation.

Note: The low-speed RC oscillator is controlled directly by the watchdog timer; its oscillation in the standby

mode is also controlled by the watchdog timer.

2) There are five ways of resetting the HOLD mode:

(1) Setting the reset pin to the lower level

(2) Having the watchdog timer or LVD function generate a reset

(3) Having an interrupt source established at one of the INT0, INT1, INT2 and INT4 pins

* INT0 and INT1 can be used in the level sense mode only.

(4) Having an interrupt source established at port 0.

(5) Having an interrupt source established in the CVD circuit

X'tal HOLD mode: Suspends instruction execution and the operation of the peripheral circuits except the base timer.

(when X’tal oscillation or low-speed RC oscillation is selected).

1) The CF, low-speed, and medium-speed RC oscillators automatically stop operation.

Note: The low-speed RC oscillator is controlled directly by the watchdog timer; its oscillation in the standby

mode is also controlled by the watchdog timer.

Note: If the base timer is run with low-speed RC oscillation selected as the base timer input clock source and the

X’tal HOLD mode is entered, the low-speed RC oscillator retains the state that is established when the X’tal

HOLD mode is entered.

2) The state of crystal oscillation established when the X'tal HOLD mode is entered is retained.

3) There are six ways of resetting the X'tal HOLD mode.

(1) Setting the reset pin to the low level

(2) Having the watchdog timer or LVD function generate a reset

(3) Having an interrupt source established at one of the INT0, INT1, INT2, and INT4 pins

* INT0 and INT1 can be used in the level sense mode only.

(4) Having an interrupt source established at port 0

(5) Having an interrupt source established in the base timer circuit

(6) Having an interrupt source established in the CVD circuit

On-chip Debugger Function

Supports software debugging with the IC mounted on the target board.

Provides 1 channel of on-chip debugger pin.

DBGP0 (P0)

Data Security Function

Protects the program data stored in flash memory from unauthorized read or copy.

Note: This data security function does not necessarily provide absolute data security.