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NOTE: The turbo mode is also supported for the Keep SPIEN active mode when the following
conditions are met:
•
A single channel will be explicitly used (bit MCSPI_MODULCTRL[Single] is set to 1).
•
The turbo mode is enabled in the configuration of the channel (bit Turbo of the
register (i)CONF).
12.2.3.6.3 Turbo Mode
The purpose of the Turbo mode is to improve the throughput of the SPI interface when a single channel
is enabled, by allowing transfers until the shift register and the receiver register are full.
This mode is programmable per channel (bit Turbo of the register (I)CONF). When several channels
are enabled, the bit Turbo of the registers MCSPI_CH(I)CONF has no effect, and the channel access to
the shift registers remains as described in
In Turbo mode, Rule 1 and Rule 2 defined in
applicable. An enabled channel can be scheduled if its receive register is full (bit RXS of the register
MCSPI_CH(I)STAT) at the time of shift register assignment until the shift register is full.
In Turbo mode, Rule 1 and Rule 2 defined in
applicable. An enabled channel can be scheduled if its receive register is full (bit RXS of the register
MCSPI_CH(I)STAT) at the time of shift register assignment until the shift register is full.
The receiver register cannot be overwritten in turbo mode. In consequence the RX_overflow bit, in
MCSPI_IRQSTATUS register is never set in this mode.
12.2.3.7 Start Bit Mode
The purpose of the start bit mode is to add an extended bit before the SPI word transmission specified
by word length WL. This feature is only available in master mode. This mode is compliant with write
command/data format as specified in LoSSI protocol.
This mode is programmable per channel (bit Start bit enable SBE of the register MCSPI_CH(I)CONF).
The polarity of the extended bit is programmable per channel and it indicates whether the next SPI
word must be handled as a command when SBPOL is cleared to 0 or as a data or a parameter when
SBPOL is set to 1 (refer to LoSSI specification [4]). Moreover start bit polarity SBPOL can be changed
dynamically during start bit mode transfer without disabling the channel for reconfiguration, in this case
you have the responsibility to configure the SBPOL bit before writing the SPI word to be transmitted in
TX register.
The start bit mode could be used at the same time as turbo mode and/or manual chip select mode. In
this case only one channel could be used, no round-robin arbitration is possible.
SPRUGX9 – 15 April 2011
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Preliminary
Section
12.2.3.3.
Section 12.2.3.3
Section 12.2.3.3
© 2011, Texas Instruments Incorporated
are applicable but Rule 3 is not
are applicable but Rule 3 is not
Multichannel Serial Port Interface (McSPI)
Architecture
1227
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