3802 GROUP USER’S MANUAL
1-32
HARDWARE
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.
Register contents
(000116)
Prescaler X
Port P0 direction register
Port P1 direction register
Port P2 direction register
Port P3 direction register
Port P4 direction register
Port P5 direction register
Port P6 direction register
Serial I/O1 status register
Serial I/O1 control register
Timer X
UART control register
Serial I/O2 control register
Prescaler 12
Timer 1
Timer XY mode register
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
(31)
(000316)
(000516)
(000716)
(000916)
(000B16)
(000D16)
(001916)
(001A16)
(001B16)
(001D16)
(002016)
(002116)
(002216)
(002316)
(002416)
(002516)
(002616)
(002716)
(002B16)
(003416)
(003616)
(003716)
(003A16)
(003B16)
(003C16)
(003D16)
(003E16)
Address
Timer 2
Prescaler Y
Timer Y
PWM control register
AD/DA control register
D-A1 conversion register
D-A2 conversion register
Interrupt edge selection register
CPU mode register
Interrupt request register 1
Interrupt request register 2
Interrupt control register 1
Interrupt control register 2
Processor status register
Program counter
0016
FF16
0016
FF16
0116
0016
11 1 0 0 0
0
0016
Contents of address FFFC16
!! ! ! ! 1
!
(PS)
(PCH)
(PCL)
Contents of address FFFD16
0016
(003F16)
10 0 0 0 0
0
FF16
00 0 0 1 0
0
0016
00 0 0 0 0
0
V
Reset Circuit
To reset the microcomputer, the RESET pin should be held at an
“L” level for 2
s 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).
Fig. 35 Internal status of microcomputer after reset
Fig. 34 Example of reset circuit
FUNCTIONAL DESCRIPTION
4.0V
0.8V
0V
VCC
RESET
Power source
voltage
Reset input
voltage
VSS
M51953AL
4
5
1
3
0.1
F
3802 group