TXZ Family
Serial Peripheral Interface
2019-02-28
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Rev. 3.0
3.3.7.2. Polarity of the Clock
To select a polarity of the clock, set
[TSPIxFMTR0]
<CKPOL>.
When
[TSPIxFMTR0]
<CKPOL>=0, TSPIxSCK outputs "Low" level signal during idle period and the first clock
edge is a rising edge.
When
[TSPIxFMTR0]
<CKPOL>=1, TSPIxSCK outputs "High" level signal during idle period and the first clock
edge is a falling edge.
3.3.7.3. TSPIxTXD Output during Idle
The level of TSPIxTXD output during idle state can be selected by
[TSPIxCR2]
<TIDLE[1:0]> (output value fixed
functional control register at the time of an idle).
The output value of TSPIxTXD which is according to a set up data at set up timing of
[TSPIxCR2]
<TIDLE[1:0]>.
However, in master operation, when "Fix to Low"(<TIDLE[1:0]>=10) or "Fix to High" (<TIDLE[1:0]>=11) is
once selected. And re-select to “Last data in previous transmission“ (<TIDLE[1:0]>=01) immediately after. Then
TSPIxTXD is kept previous setting until starts next transmission.
When a underrun error occurs with a final data output at the time of slave operation, the value specified in the
[TSPIxCR2]
<TXDEMP> is outputted during frame transmission, and it changes to the data output value
performed at the end by the end of transmission.
The frame interval period during burst transfer keep the last data of previous transfer. "High" is output if there is
no data equivalent to the last data of the previous transfer, such as immediately after reset release.
Table 3.5 TSPIxTXD output during idle state
[TSPIxCR2]
<TIDLE[1:0]>
Output
00
Hi-Z
01
Last data of the previous transfer
10
Low
11
High
Note: When transmitting by master operation of SIO mode, undefined value is output one clock (TSPIxSCK) early
before transmission starts.