SH7751 Group, SH7751R Group
Section 15 Serial Communication Interface (SCI)
R01UH0457EJ0301 Rev. 3.01
Page 669 of 1128
Sep 24, 2013
M: Receive
margin
(
%
)
N: Ratio of clock frequency to bit rate (N = 16)
D: Clock duty cycle (D = 0 to 1.0)
L: Frame length (L = 9 to 12)
F: Absolute deviation of clock frequency
From equation (1), if F = 0 and D = 0.5, the receive margin is 46.875
%
, as given by equation (2).
When D = 0.5 and F = 0:
M = (0.5 – 1/(2
×
16))
×
100
%
= 46.875
%
............................................ (2)
This is a theoretical value. A reasonable margin to allow in system designs is 20
%
to 30
%
.
When Using the DMAC:
When an external clock source is used as the serial clock, the transmit
clock should not be input until at least 5 peripheral operating clock cycles after SCTDR1 is
updated by the DMAC. Incorrect operation may result if the transmit clock is input within 4 cycles
after SCTDR1 is updated. (See figure 15.26)
SCK
TDRE
TxD
D0
D1
D2
D3
D4
D5
D6
D7
t
Note: When operatin
g
on an external clock, set t > 4.
Figure 15.26 Example of Synchronous Transmission by DMAC
When SCRDR1 is read by the DMAC, be sure to set the SCI receive-data-full interrupt (RXI) as
the activation source with bits RS3 to RS0 in CHCR.
When Using Synchronous External Clock Mode:
•
Do not set TE or RE to 1 until at least 4 peripheral operating clock cycles after external clock
SCK has changed from 0 to 1.
•
Only set both TE and RE to 1 when external clock SCK is 1.
Содержание SH7751 Group
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Страница 226: ...Section 5 Exceptions SH7751 Group SH7751R Group Page 172 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 264: ...Section 7 Instruction Set SH7751 Group SH7751R Group Page 210 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 320: ...Section 9 Power Down Modes SH7751 Group SH7751R Group Page 266 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 344: ...Section 10 Clock Oscillation Circuits SH7751 Group SH7751R Group Page 290 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 388: ...Section 12 Timer Unit TMU SH7751 Group SH7751R Group Page 334 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 800: ...Section 17 Smart Card Interface SH7751 Group SH7751R Group Page 746 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 848: ...Section 19 Interrupt Controller INTC SH7751 Group SH7751R Group Page 794 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 876: ...Section 20 User Break Controller UBC SH7751 Group SH7751R Group Page 822 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1036: ...Section 22 PCI Controller PCIC SH7751 Group SH7751R Group Page 982 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1152: ...Appendix C Mode Pin Settings SH7751 Group SH7751R Group Page 1098 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
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