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Rev. 2.50
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Rev. 2.50
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HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
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
SIM2
SIM�
SIM0
PCKEN
PCKP�
PCKP0
SIMEN
—
SIMD
D�
D6
D5
D4
D3
D2
D�
D0
SIMC2
D�
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
SIM Registers List
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 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.
•
SIMD Register
Bit
7
6
5
4
3
2
1
0
Name
D�
D6
D5
D4
D3
D2
D�
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
×
×
×
×
×
×
×
×
“x”: �nknown
There are also two control registers for the SPI interface, SIMC0 and SIMC2. Note that the SIMC2
register also has the name SIMA which is used by the I
2
C function. The SIMC1 register is not used
by the SPI function, only by the I
2
C function. Register SIMC0 is used to control the enable/disable
function and to set the data transmission clock frequency. Although not connected with the SPI
function, the SIMC0 register is also used to control the Peripheral Clock Prescaler. Register SIMC2
is used for other control functions such as LSB/MSB selection, write collision flag etc.