TXZ Family
Serial Peripheral Interface
2019-02-28
26 / 67
Rev. 3.0
3.3. Operation
3.3.1. Transfer clock
3.3.1.1. Master operation
The transfer clock generation circuit is shown Figure 3.10.
Transfer clock
(TSPIxSCK)
Baud Rate
Genenrator
Prescaler Clock
Φ
T0
Prescaler
1/2
Φ
Tx
1/1
1/2
1/4
1/8
1/16
1/32
1/64
1/128 1/256 1/512
Figure 3.10 Transfer clock generation circuit
The prescale
r dividing ΦT0 from 1/1 to 1/512 (ΦT0 to ΦT256). Divided clock can be selected by
[TSPIxBR]
<BRCK>.
The example of calculation of transfer clock frequency (transfer clock) is shown below.
transfer clock =
ΦT0 ×
[TSPIxBR]
<BRCK> (1/x) ×
[TSPIxBR]
<BRS> (1/N) × 1/2
(x= 1,2,4,8,16 to 256, 512, N= 1,2,3,4, to 16)
At this time, please keep below condition
The case of
[TSPIxCR2]
<RXDLY>=0, 1/2 ×f
clk
= transfer clock
The case of
[TSPIxCR2]
<RXDLY>=1, 1/4 ×f
clk
≥
transfer clock
and
f
clk
≥
ΦT0