Holtek HT32F54231 User Manual page 460

32-Bit Arm ® Cortex ® -M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
Bits Field
[10:8] FORMAT
[3:0] DFL
Rev. 1.00
Descriptions
SPI Data Transfer Format
These three bits are used to determine the data transfer format of the SPI
interface.
FORMAT [2:0] CPOL
001 0
010 0
110 1
101 1
Others Reserved
CPOL: Clock Polarity
0: SCK Idle state is low
1: SCK Idle state is high
CPHA: Clock Phase
0: Data is captured on the first SCK clock edge
1: Data is captured on the second SCK clock edge
Data Frame Length
Selects the data transfer frame from 1 bit to 16 bits.
DFL[3:0] SPI Serial Mode
0001 1 bit
0010 2 bits
0011 3 bits
0100 4 bits
0101 5 bits
0110 6 bits
0111 7 bits
1000 8 bits
1001 9 bits
... ...
1111 15 bits
0000 16 bits
Notes: 1. The total number of data bits is determined by the DFL field configuration
together with the selected SPI device transmission mode.
2. Taking the 16-bit data transmission for example, the DFL setting can be
figured out as follows
In the Serial Mode: Data frame length = 16/1 = 16, DFL = 0x0;
In the Dual SPI Mode: Data frame length = 16/2 = 8, DFL = 0x8;
3. Dual mode only supports 16-bit data length.
460 of 576
CPHA
0
1
0
1
SPI Dual Mode
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16 bits
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January 28, 2022