M38258MCM Datasheet, PDF (37/70 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3825 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
RESET CIRCUIT
To reset the microcomputer, 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 VCC (Min.) and
5.5 V, and the oscillation should be stable), and reset is released.
After the reset is completed, the program starts from the address
contained in address FFFD16 (high-order byte) and address
FFFC16 (low-order byte).
Make sure that the reset input voltage is less than 0.2 V for VCC
(Min.).
RESET
Power source
voltage
VCC
0V
Reset input
voltage
0V
Power on
(Note)
0.2VCC
Note: Reset release voltage : VCC = VCC(Min.)
RESET
VCC
Power source voltage
detection circuit
Fig. 36 Example of reset circuit
( 1 ) Port P0
Address Register contents
0 0 0 0 16
0016
( 2 ) Port P1
0 0 0 2 16
0016
( 3 ) Port P1 output control register 0 0 0 3 16
0016
( 4 ) Port P2
0 0 0 4 16
0016
( 5 ) Port P2 direction register
0 0 0 5 16
0016
( 6 ) Port P3
0 0 0 6 16
0016
( 7 ) Port P4
0 0 0 8 16
0016
( 8 ) Port P4 direction register
0 0 0 9 16
0016
( 9 ) Port P5
0 0 0 A 16
0016
(10) Port P5 direction register
0 0 0 B 16
0016
(11) Port P6
0 0 0 C 16
0016
(12) Port P6 direction register
0 0 0 D 16
0016
(13) Port P7
0 0 0 E 16
0016
(14) Port P7 direction register
0 0 0 F 16
0016
(15) Port P8
0 0 1 0 16
0016
(16) Port P8 direction register
0 0 1 1 16
0016
(17) PULL register A
0 0 1 6 16
0116
(18) PULL register B
0 0 1 7 16
0016
(19) Serial I/O status register
0 0 1 9 16 1 0 0 0 0 0 0 0
(20) Serial I/O control register
0 0 1 A 16
0016
(21) UART control register
0 0 1 B 16 1 1 1 0 0 0 0 0
(22) Timer X (low)
0 0 2 0 16
FF16
(23) Timer X (high)
0 0 2 1 16
FF16
(24) Timer Y (low)
0 0 2 2 16
FF16
(25) Timer Y (high)
0 0 2 3 16
FF16
(26) Timer 1
0 0 2 4 16
FF16
(27) Timer 2
0 0 2 5 16
0116
(28) Timer 3
0 0 2 6 16
FF16
(29) Timer X mode register
0 0 2 7 16
00001166
(30) Timer Y mode register
0 0 2 8 16
0016
(31) Timer 123 mode register
0 0 2 9 16
0016
(32) Clock output control register 0 0 2 A 16
0016
(33) A-D control register
0 0 3 4 16 0 0 0 0 1 0 0 0
(34) Segment output enable register
0 0 3 8 16
0016
(35) LCD mode register
0 0 3 9 16
0016
(36) Interrupt edge selection register
0 0 3 A 16
0016
(37) CPU mode register
0 0 3 B 16 0 1 0 0 1 0 0 0
(38) Interrupt request register 1 0 0 3 C 16
0016
(39) Interrupt request register 2 0 0 3 D 16
0016
(40) Interrupt control register 1 0 0 3 E 16
0016
(41) Interrupt control register 2 0 0 3 F 16
0016
(42) Processor status register
(PS) ! ! ! ! ! 1 ! !
(43) Program counter
( P C H ) Contents of address FFFD 16
( P C L ) Contents of address FFFC 16
Note : The contents of all other registers and RAM are undefined after
reset, so they must be initialized by software.
! : Undefined
Fig. 37 Internal state of microcomputer immediately after re-
set
37