M38005M2FS View Datasheet(PDF) - MITSUBISHI ELECTRIC

Part Name

Description

Manufacturer

M38005M2FS

8-BIT SINGLE-CHIP MICROCOMPUTER

MITSUBISHI ELECTRIC  

HARDWARE

FUNCTIONAL DESCRIPTION

Reset Circuit

To reset the microcomputer, the RESET pin should be held at an

“L” level for 2 µs or more. Then the RESET pin is returned to an “H”

level (the power source voltage should be between 3.0 V and 5.5

V, and between 4.0 V and 5.5 V for extended operating tempera-

ture version), reset is released. Internal operation does not begin

until after 8 to 13 XIN clock cycles are completed. After the reset is

completed, the program starts from the address contained in ad-

dress FFFD16 (high-order byte) and address FFFC16 (low-order

byte).

Make sure that the reset input voltage is less than 0.6 V for VCC of

3.0 V (Extended operating temperature version: the reset input

voltage is less than 0.8 V for VCC of 4.0 V).

Power source

voltage 0V

3.0V (Note 1)

Reset input

voltage 0V

0.6V (Note 2)

Note 1 : Extended operating temperature version : 4.0V

Note 2 : Extended operating temperature version : 0.8V

1

5

M51953AL

4

0.1 µ F

3

Fig. 22 Example of reset circuit

VCC

RESET

VSS

3800 group

(1) Port P0 direction register

(2) Port P1 direction register

Address Register contents

(000116) • • •

0016

(000316) • • •

0016

(3) Port P2 direction register (000516) • • •

0016

(4) Port P3 direction register (000716) • • •

0016

(5) Port P4 direction register (000916) • • •

0016

(6) Port P5 direction register (000B16) • • •

0016

(7) Port P6 direction register (000D16) • • •

0016

(8) Port P7 direction register (000F16) • • •

0016

(9) Serial I/O status register (001916) • • • 1 0 0 0 0 0 0 0

(10) Serial I/O control register

(11) UART control register

(001A16) • • •

0016

(001B16) • • • 1 1 1 0 0 0 0 0

(12) Prescaler 12

(13) Timer 1

(14) Timer 2

(002016) • • •

(002116) • • •

(002216) • • •

FF16

0116

FF16

(15) Timer XY mode register (002316) • • •

0016

(16) Prescaler X

(17) Timer X

(002416) • • •

(002516) • • •

FF16

FF16

(18) Prescaler Y

(002616) • • •

FF16

(19) Timer Y

(002716) • • •

FF16

(20) Interrupt edge selection register (003A16) • • •

0016

(21) CPU mode register

(003B16) • • • 0 0 0 0 0 0 V 0

(22) Interrupt request register 1 (003C16) • • •

0016

(23) Interrupt request register 2 (003D16) • • •

0016

(24) Interrupt control register 1 (003E16) • • •

0016

(25) Interrupt control register 2 (003F16) • • •

0016

(26) Processor status register

(PS) ! ! ! ! ! 1 ! !

(27) Program counter

(PCH) Contents of address FFFD16

(PCL) Contents of address FFFC16

Note. ! : Undefined

V : The initial values of CM1 are determined by the level at the

CNVSS pin.

The contents of all other registers and RAM are undefined

after a reset, so they must be initialized by software.

Fig. 23 Internal status of microcomputer after reset

1-26

3800 GROUP USER’S MANUAL

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