Holtek HT66F20-1 Manual page 152

exists a relationship between the system clock, f
Standard or Fast mode operation, users must take care of the selected system clock frequency and
the configured debounce time to match the criterion shown in the following table.
I 2 C Debounce Time Selection
�o de�ounce
� syste� clock de�ounce
4 syste� clock de�ounce
I C Registers
2
There are three control registers associated with the I
data register, SIMD. The SIMD register, which is shown in the above SPI section, is used to store
the data being transmitted and received on the I
the I C bus, the actual data to be transmitted must be placed in the SIMD register. After the data is
2
received from the I
or reception of data from the I
Note that the SIMA register also has the name SIMC2 which is used by the SPI function. Bit SIMEN
and bits SIM2~SIM0 in register SIMC0 are used by the I
Register
Name
SIMC0 SIM�
SIMC1 HCF
SIMD D7
SIMA IICA�
Rev. 1.40
HT66F20-1/HT66F30-1/HT68F20-1/HT68F30-1
I 2 C Standard Mode (100kHz)
f
SYS
f
SYS
f
SYS
I C Minimum f
2
S T A R T s i g n a l
f r o m
S e n d s l a v e a d d r e s s
a n d R / W
A c k n o w l e d g e
f r o m
S e n d d a t a b y t e
f r o m
A c k n o w l e d g e
f r o m
S T O P s i g n a l
f r o m
C bus, the microcontroller can read it from the SIMD register. Any transmission
2
C bus must be made via the SIMD register.
2
7 6 5
SIM1 SIM0 PCKE�
HA�S HBB
D� D5
IICA5 IICA4 IICA�
I C Registers List
2
15�
Flash MCU with EEPROM
, and the I C debounce time. For either the I
2
SYS
I 2 C Fast Mode (400kHz)
> �MHz f
SYS
> 4MHz f
SYS
> 8MHz f
SYS
Frequency
SYS
M a s t e r
b i t f r o m M a s t e r
s l a v e
M a s t e r
s l a v e
M a s t e r
C bus, SIMC0, SIMC1 and SIMA, and one
2
C bus. Before the microcontroller writes data to
2
C interface.
2
Bit
4 3 2
PCKP1 PCKP0
HTX TXAK SRW
D4 D� D�
IICA� IICA1
C
2
> 5MHz
> 10MHz
> �0MHz
1 0
SIME� —
IAMWU RXAK
D1 D0
IICA0 D0
�ove��e� ��� �01�