
Rev. 1.20
128
November 20, 2019
Rev. 1.20
129
November 20, 2019
HT66F2740
12V High Current Flash MCU
HT66F2740
12V High Current Flash MCU
I
2
C Registers
There are three control registers associated with the I
2
C bus, SIMC0, SIMC1 and SIMTOC, one
address register SIMA and one data register, SIMD. Note that the SIMC1, SIMD, SIMA and
SIMTOC registers and their POR values are only available when the I
2
C mode is selected by
properly configuring the UMD and SIM2~SIM0 bits in the SIMC0 register.
Register
Name
Bit
7
6
5
4
3
2
1
0
SIMC0
SIM2
SIM1
SIM0
UMD
SIMDEB1 SIMDEB0 SIMEN
SIMICF
SIMC1
HCF
HAAS
HBB
HTX
TXAK
SRW
IAMWU
RXAK
SIMD
D7
D6
D5
D4
D3
D2
D1
D0
SIMA
A6
A5
A4
A3
A2
A1
A0
D0
SIMTOC SIMTOEN SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS2 SIMTOS1 SIMTOS0
I
2
C Register List
I
2
C Data Register
The SIMD register is used to store the data being transmitted and received. The same register is used
by both the SPI and I
2
C functions. Before the device 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
device 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.
• SIMD Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
“x”
: unknown
Bit 7~0
D7~D0
: USIM SPI/I
2
C data register bit 7 ~ bit 0
I
2
C Address Register
The SIMA register is also used by the SPI interface but has the name SIMC2. The
SIMA register is the location where the 7-bit slave address of the slave device is
stored. Bits 7~1 of the SIMA register define the device slave address. Bit 0 is not
defined. When a master device, which is connected to the I
2
C bus, sends out an
address, which matches the slave address in the SIMA register, the slave device will be
selected.
• SIMA Register
Bit
7
6
5
4
3
2
1
0
Name
A6
A5
A4
A3
A2
A1
A0
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~1
A6~A0
: I
2
C slave address
A6~A0 is the I
2
C slave address bit 6~bit 0.
Bit 0
D0
: Reserved bit, can be read or written
I
2
C Control Registers
There are three control registers for the I
2
C interface, SIMC0, SIMC1 and SIMTOC. The SIMC0
register is used to control the enable/disable function and to set the data transmission clock
frequency. The SIMC1 register contains the relevant flags which are used to indicate the I
2
C