M38002M4 Datasheet, PDF (40/173 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

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