M38027E8SP Datasheet, PDF (28/51 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3802 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
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 4.0 V and 5.5
V), reset is released. Internal operation begin until after 8 to 13 XIN
clock cycles are completed. After the reset is completed, the pro-
gram 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 0.6 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
Reset input
voltage ^0V
4.0V
0.8V
1
5
M51953AL
4
0.1 µ F
3
Fig. 26 Example of reset circuit
VCC
RESET
VSS
3802 group
(1) Port P0 direction register
Address Register contents
(000116) · · ·
0016
(2) Port P1 direction register
(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) Serial I/O1 status register
(001916) · · · 1 0 0 0 0 0 0 0
(9) Serial I/O1 control register
(001A16) · · ·
0016
(10) UART control register
(001B16) · · · 1 1 1 0 0 0 0 0
(11) Serial I/O2 control register
(001D16) · · ·
0016
(12) Prescaler 12
(002016) · · ·
FF16
(13) Timer 1
(14) Timer 2
(002116) · · ·
(002216) · · ·
0116
FF16
(15) Timer XY mode register
(002316) · · ·
0016
(16) Prescaler X
(002416) · · ·
FF16
(17) Timer X
(002516) · · ·
FF16
(18) Prescaler Y
(002616) · · ·
FF16
(19) Timer Y
(002716) · · ·
FF16
(20) PWM control register
(002B16) · · ·
0016
(21) AD/DA control register
(22) D-A1 conversion register
(003416) · · · _{0 0 0 0 1 0 0 0}
(003616) · · ·
0016
(23) D-A2 conversion register
(003716) · · ·
0016
(24) Interrupt edge selection register (003A16) · · ·
0016
(25) CPU mode register
(003B16) · · · 0 0 0 0 0 0 V 0
(26) Interrupt request register 1
(003C16) · · ·
0016
(27) Interrupt request register 2
(003D16) · · ·
0016
(28) Interrupt control register 1
(003E16) · · ·
0016
(29) Interrupt control register 2
(003F16) · · ·
0016
(30) Processor status register
(PS) ! ! ! ! ! 1 ! !
(31) 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. 27 Internal status of microcomputer after reset
28