Rev. 2.10
72
���� 02� 201�
Rev. 2.10
73
���� 02� 201�
HT68F20/HT68F30/HT68F40/HT68F50/HT68F60
HT68FU30/HT68FU40/HT68FU50/HT68FU60
Enhanced I/O Flash Type 8-Bit MCU with EEPROM
HT68F20/HT68F30/HT68F40/HT68F50/HT68F60
HT68FU30/HT68FU40/HT68FU50/HT68FU60
Enhanced I/O Flash Type 8-Bit MCU with EEPROM
Reset Initial Conditions
The different types of reset described affect the reset flags in different ways. These flags, known
as PDF and TO are located in the status register and are controlled by various microcontroller
operations, such as the SLEEP or IDLE Mode function or Watchdog Timer. The reset flags are
shown in the table:
T0
RESET Conditions
0
0
Power-on reset
�
�
RES or LVR reset d�ring NORMAL or SLOW Mode operation
1
�
WDT time-o�t reset d�ring NORMAL or SLOW Mode operation
1
1
WDT time-o�t reset d�ring IDLE or SLEEP Mode operation
Note: "�" stands for �nchanged
The following table indicates the way in which the various components of the microcontroller are
affected after a power-on reset occurs.
Item
Condition After RESET
Program Co�nter
Reset to zero
Interr�pts
A�� interr�pts wi�� be disab�ed
WDT
C�ear after reset� WDT begins co�nting
Timer/Event Co�nter
Timer Co�nter wi�� be t�rned off
Inp�t/O�tp�t Ports
I/O ports wi�� be set�p as inp�ts
Stack Pointer
Stack Pointer wi�� point to the top of the stack
The different kinds of resets all affect the internal registers of the microcontroller in different ways.
To ensure reliable continuation of normal program execution after a reset occurs, it is important to
know what condition the microcontroller is in after a particular reset occurs. The following table
describes how each type of reset affects each of the microcontroller internal registers. Note that where
more than one package type exists the table will reflect the situation for the larger package type.
HT68F20
Register
Reset (Power-on)
RES or LVR Reset
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE)
MP0
1 x x x x x x x
1 x x x x x x x
1 x x x x x x x
1 � � � � � � �
MP1
1 x x x x x x x
1 x x x x x x x
1 x x x x x x x
1 � � � � � � �
BP
- - - - - - -0
- - - - - - -0
- - - - - - -0
- - - - - - -�
ACC
x x x x x x x x
� � � � � � � �
� � � � � � � �
� � � � � � � �
PCL
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
TBLP
x x x x x x x x
� � � � � � � �
� � � � � � � �
� � � � � � � �
TBLH
- - x x x x x x
- - �� ����
- - � � � � � �
- - �� ����
TBHP
- - - - - - x x
- - - - - -��
- - - - - -��
- - - - - - ��
STATUS
- - 0 0 x x x x
- - � � � � � �
- - 1� ����
- - 11 ����
SMOD
0 0 0 0 0 0 11
0 0 0 0 0 0 11
0 0 0 0 0 0 11
� � � � � � � �
LVDC
- - 00 - 000
- - 00 - 000
- - 00 - 000
- - �� - ���
INTEG
- - - - 0000
- - - - 0000
- - - - 0000
- - - - ����
WDTC
0 111 1 0 1 0
0 111 1 0 1 0
0 111 1 0 1 0
� � � � � � � �
TBC
0 0 11 0 111
0 0 11 0 111
0 0 11 0 111
� � � � � � � �
INTC0
- 0 0 0 0 0 0 0
- 0 0 0 0 0 0 0
- 0 0 0 0 0 0 0
- � � � � � � �
INTC1
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
� � � � � � � �
INTC2
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
� � � � � � � �
MFI0
- - 0 0 - - 0 0
- - 0 0 - - 0 0
- - 0 0 - - 0 0
- - � � - - � �
MFI1
- - 0 0 - - 0 0
- - 0 0 - - 0 0
- - 0 0 - - 0 0
- - � � - - � �