M38207E8FP Datasheet, PDF (39/66 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3820 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 2.5 V and
5.5 V, and the oscillation should be stable), reset is released. In or-
der to give the XIN clock time to stabilize, internal operation does
not begin until after 8200 XIN clock cycles (timer 1 and timer 2 are
connected together and 512 cycles of f(XIN)/16) are complete. Af-
ter 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 0.5 V for VCC of
2.5 V (Extended operating temperature version: the reset input
voltage is less than 0.6V for VCC of 3.0V).
RESET
Power source
voltage
VCC
0V
Power on
(Note)
Reset input
voltage
0V
0.2VCC
Note. Reset release voltage : VCC = 2.5V
(Extended operating temperature version : 3.0V)
RESET
VCC
Power source voltage
detection circuit
Fig. 32 Example of reset circuit
( 1 ) Port P0 direction register
Address Register contents
(000116) • • •
0016
( 2) Port P1 direction register (000316) • • •
0016
( 3) Port P2 direction register
( 4) Port P4 direction register
( 5) Port P5 direction register
(000516) • • •
(000916) • • •
(000B16) • • •
0016
0016
0016
( 6) Port P6 direction register ^{(000D16) • • •}
0016
( 7) Port P7 direction register (000F16) • • •
0016
( 8) PULL register A
(001616) • • • 0 0 0 0 1 0 1 1
( 9 ) PULL register B
(001716) • • •
0016
(10) Serial I/O1 status register (001916) • • • 1 0 0 0 0 0 0 0
(11) Serial I/O1 control register (001A16) • • •
0016
(12) UART control register
(001B16) • • • 1 1 1 0 0 0 0 0
(13) Serial I/O2 control register (001D16) • • •
(14) Timer X (low-order)
(002016) • • •
0016
FF16
(15) Timer X (high-order)
(002116) • • •
FF16
(16) Timer Y (low-order)
(002216) • • •
FF16
(17) Timer Y (high-order)
(002316) • • •
FF16
(18) Timer 1
(002416) • • •
FF16
(19) Timer 2
(002516) • • •
0116
(20) Timer 3
(002616) • • •
FF16
(21) Timer X mode register
(002716) • • •
0016
(22) Timer Y mode register
(002816) • • •
0016
(23) Timer 123 mode register (002916) • • •
0016
(24) φ output control register (002A16) • • •
0016
(25) Watchdog timer control register (003716) • • • 0 1 1 1 1 1 1 1
(26) Segment output enable register (003816) • • •
0016
(27) LCD mode register
(003916) • • •
0016
(28) Interrupt edge selection register (003A16) • • •
0016
(29) CPU mode register
(003B16) • • • 0 1 0 0 1 0 0 0
(30) Interrupt request register 1 (003C16) • • •
0016
(31) Interrupt request register 2 (003D16) • • •
0016
(32) Interrupt control register 1 (003E16) • • •
0016
(33) Interrupt control register 2 (003F16) • • •
0016
(34) Processor status register
(PS) ! ! ! ! ! 1 ! !
(35) Program counter
(PCH) Contents of address FFFD16
(PCL) Contents of address FFFC16
Note. ! : Undefined
The contents of all other registers and RAM are undefined
at poweron reset, so they must be initialized by software.
Fig. 33 Internal state of microcomputer immediately after re-
set
39