Figure 249. Ti Mode - Slave Mode, Single Transfer; Figure 250. Ti Mode - Slave Mode, Continuous Transfer - STMicroelectronics STM32F405 Reference Manual

RM0090
In Slave mode
- Slave mode, continuous
moment when the MISO pin state changes to HI-Z. Any baud rate can be used thus allowing
to determine this moment with optimal flexibility. However, the baud rate is generally set to
the external master clock baud rate. The time for the MISO signal to become HI-Z (t
depends on internal resynchronizations and on the baud rate value set in through BR[2:0] of
SPI_CR1 register. It is given by the formula:
Note: This feature is not available for Motorola SPI communications (FRF bit set to 0).
To detect TI frame errors in Slave transmitter only mode by using the Error interrupt (ERRIE
= 1), the SPI must be configured in 2-line unidirectional mode by setting BIDIMODE and
BIDIOE to 1 in the SPI_CR1 register. When BIDIMODE is set to 0, OVR is set to 1 because
the data register is never read and error interrupt are always generated, while when
BIDIMODE is set to 1, data are not received and OVR is never set.
(Figure 249: TI mode - Slave mode, single transfer
transfer), the SPI baud rate prescaler is used to control the
t
baud_rate
--------------------- -
4 t
+
2

Figure 249. TI mode - Slave mode, single transfer

Figure 250. TI mode - Slave mode, continuous transfer

DocID018909 Rev 11
t
× < < --------------------- -
t
pclk release
Serial peripheral interface (SPI)
and Figure 250: TI mode
baud_rate
×
6 t
+
pclk
2
)
release
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