Spi Registers - Holtek HT68F Series Manual

HT68F20/HT68F30/HT68F40/HT68F50/HT68F60
HT68FU30/HT68FU40/HT68FU50/HT68FU60
Enhanced I/O Flash Type 8-Bit 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 C interface.
2
Register
Name
7
SIMC0 SIM2
SIMD D7
SIMC2 D7
The SIMD register is used to store the data being transmitted and received. The same register is used
by both the SPI and I
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
Name D7
R/W R/W
POR ×
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
by the SPI function, only by the I
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.
Rev. 2.10
6 5 4
SIM1 SIM0 PCKEN
D6 D5 D�
D6 CKPOLB CKEG
SIM Registers List
C functions. Before the device writes data to the SPI bus, the actual data to
2
6 5 4
D6 D5 D�
R/W R/W R/W
× × ×
C function. Register SIMC0 is used to control the enable/disable
2
171
Bit
3 2 1
PCKP1 PCKP0 SIMEN
D3 D2 D1
MLS CSEN WCOL
3 2 1
D3 D2 D1
R/W R/W R/W
× × ×
C function. The SIMC1 register is not used
2
0
—
D0
TRF
0
D0
R/W
×
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