
Rev. 1.20
120
November 20, 2019
Rev. 1.20
121
November 20, 2019
HT66F2740
12V High Current Flash MCU
HT66F2740
12V High Current Flash MCU
The SPI function in the device offers the following features:
• Full duplex synchronous data transfer
• Both Master and Slave modes
•
LSB first or MSB first data transmission modes
•
Transmission complete flag
• Rising or falling active clock edge
The status of the SPI interface pins is determined by a number of factors such as whether the device
is in the master or slave mode and upon the condition of certain control bits such as CSEN and
SIMEN.
SIMD
TX/RX Shift Register
SDI Pin
Clock
Edge/Polarity
Control
CKEG
CKPOLB
Clock
Source
Select
f
SYS
f
SUB
PTM CCRP match frequency/2
SCK Pin
CSEN
Busy
Status
SDO Pin
SCS Pin
Data Bus
WCOL
TRF
SIMICF
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 control registers, SIMC0 and SIMC2. Note that the SIMC2 and
SIMD registers and their POR values are only available when the SPI 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
SIMC2
D7
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
SIMD
D7
D6
D5
D4
D3
D2
D1
D0
SPI Register List
SPI 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 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.