ST72521R9-Auto STMicroelectronics, ST72521R9-Auto Datasheet - Page 129

• Manufacturer Part Number: ST72521R9-Auto
• Description: 8-bit MCU for automotive
• Manufacturer: STMicroelectronics

Specifications of ST72521R9-Auto

• Hdflash Endurance: 100 cycles, data retention 20 years
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator and bypass for external clock
• 4 Power Saving Modes: Halt, Active Halt, Wait and Slow

ST72521xx-Auto
14.4
Note:
Note:
The SPIF bit can be cleared during a second transmission; however, it must be cleared
before the second SPIF bit in order to prevent an Overrun condition (see
(OVR) on page
Clock phase and clock polarity
Four possible timing relationships may be chosen by software, using the CPOL and CPHA
bits (see
The idle state of SCK must correspond to the polarity selected in the SPICSR register (by
pulling up SCK if CPOL = 1 or pulling down SCK if CPOL = 0).
The combination of the CPOL clock polarity and CPHA (clock phase) bits selects the data
capture clock edge
Figure 59
The diagram may be interpreted as a master or slave timing diagram where the SCK pin, the
MISO pin, the MOSI pin are directly connected between the master and the slave device.
If CPOL is changed at the communication byte boundaries, the SPI must be disabled by
resetting the SPE bit.
Figure
shows an SPI transfer with the four combinations of the CPHA and CPOL bits.
131).
59).
Doc ID 17660 Rev 1
Serial peripheral interface (SPI)
Overrun condition
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