Rev. 1.50
130
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Rev. 1.50
131
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HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
SPI Master/Slave Connection
SPI Block Diagram
SPI Registers
There are three internal registers which control the overall operation of the SPI interface. These are
the SIMD data register and two registers SIMC0 and SIMC2. Note that the SIMC1 register is only
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
SIMC�
D�
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
SIMD
D�
D6
D5
D4
D3
D�
D1
D0
SPI Registers List
SIMD 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 devices write data to the SPI bus, the actual data to
be transmitted must be placed in the SIMD register. After the data is received from the SPI bus, the
device can read it from the SIMD register. Any transmission or reception of data from the SPI bus
must be made via the SIMD register.
Bit
7
6
5
4
3
2
1
0
Name
D�
D6
D5
D4
D3
D�
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”: �nknown