Rev. 1.50
136
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Rev. 1.50
13�
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HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
S T A R T s i g n a l
f r o m M a s t e r
S e n d s l a v e a d d r e s s
a n d R / W b i t f r o m M a s t e r
A c k n o w l e d g e
f r o m s l a v e
S e n d d a t a b y t e
f r o m M a s t e r
A c k n o w l e d g e
f r o m s l a v e
S T O P s i g n a l
f r o m M a s t e r
The SIMDEB1 and SIMDEB0 bits determine the debounce time of the I
2
C interface. This uses
the system clock to in effect add a debounce time to the external clock to reduce the possibility
of glitches on the clock line causing erroneous operation. The debounce time, if selected, can be
chosen to be either 2 or 4 system clocks. To achieve the required I
2
C data transfer speed, there
exists a relationship between the system clock, f
SYS
, and the I
2
C debounce time. For either the I
2
C
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
I
2
C Standard Mode (100kHz)
I
2
C Fast Mode (400kHz)
No Devo�nce
f
SYS
> � MHz
f
SYS
> 5 MHz
� system clock debo�nce
f
SYS
> 4 MHz
f
SYS
> 10 MHz
4 system clock debo�nce
f
SYS
> � MHz
f
SYS
> �0 MHz
I
2
C Minimum f
SYS
Frequency
I
2
C Registers
There are three control registers associated with the I
2
C bus, SIMC0, SIMC1 and SIMTOC, one
slave address register, SIMA, and one 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
2
C bus. Before
the microcontroller writes data to the I
2
C bus, the actual data to be transmitted must be placed in the
SIMD register. After the data is received from the I
2
C bus, the microcontroller can read it from the
SIMD register. Any transmission or reception of data from the I
2
C bus must be made via the SIMD
register.
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
2
C interface.
Register
Name
Bit
7
6
5
4
3
2
1
0
SIMC0
SIM�
SIM1
SIM0
—
SIMDEB1 SIMDEB0
SIMEN
SIMICF
SIMC1
HCF
H��S
HBB
HTX
TX�K
SRW
I�MWU
RX�K
SIM�
IIC�6
IIC�5
IIC�4
IIC�3
IIC��
IIC�1
IIC�0
D0
SIMD
D�
D6
D5
D4
D3
D�
D1
D0
SIMTOC SIMTOEN SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS� SIMTOS1 SIMTOS0
I
2
C Registers List