Section 13 Serial Communication Interface (SCI)
Rev. 1.00 Mar. 12, 2008 Page 478 of 1178
REJ09B0403-0100
13.7.4
Receive Data Sampling Timing and Reception Margin
Only the internal clock generated by the internal baud rate generator can be used as a
communication clock in smart card interface mode. In this mode, the SCI can operate using a
basic clock with a frequency of 32, 64, 372, or 256 times the bit rate according to the BCP1 and
BCP0 settings (the frequency is always 16 times the bit rate in normal asynchronous mode). At
reception, the falling edge of the start bit is sampled using the internal basic clock in order to
perform internal synchronization. Receive data is sampled at the 16th, 32nd, 186th and 128th
rising edges of the basic clock pulses so that it can be latched at the center of each bit as shown in
figure 13.25. The reception margin here is determined by the following formula.
M =
(0.5 – ) – (L – 0.5) F – (1 + F)
× 100 [%]
... Formula (1)
2N
1
N
D – 0.5
M:
N:
D:
L:
F:
Reception margin (%)
Ratio of bit rate to clock (N = 32, 64, 372, 256)
Clock duty (D = 0 to 1.0)
Frame length (L = 10)
Absolute value of clock rate deviation
Assuming values of F = 0, D = 0.5, and N = 372 in formula (1), the reception margin is
determined by the formula below.
M = (0.5 – 1/2 x 372) x 100 [%] = 49.866%
Содержание H8S Family
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Страница 152: ...Section 5 Interrupt Controller Rev 1 00 Mar 12 2008 Page 104 of 1178 REJ09B0403 0100...
Страница 206: ...Section 6 Bus Controller BSC Rev 1 00 Mar 12 2008 Page 158 of 1178 REJ09B0403 0100...
Страница 420: ...Section 9 14 Bit PWM Timer PWMX Rev 1 00 Mar 12 2008 Page 372 of 1178 REJ09B0403 0100...
Страница 476: ...Section 12 Watchdog Timer WDT Rev 1 00 Mar 12 2008 Page 428 of 1178 REJ09B0403 0100...
Страница 552: ...Section 14 CRC Operation Circuit CRC Rev 1 00 Mar 12 2008 Page 504 of 1178 REJ09B0403 0100...
Страница 588: ...Section 15 Serial Communication Interface with FIFO SCIF Rev 1 00 Mar 12 2008 Page 540 of 1178 REJ09B0403 0100...
Страница 632: ...Section 17 Synchronous Serial Communication Unit SSU Rev 1 00 Mar 12 2008 Page 584 of 1178 REJ09B0403 0100...
Страница 712: ...Section 18 I2 C Bus Interface IIC Rev 1 00 Mar 12 2008 Page 664 of 1178 REJ09B0403 0100...
Страница 804: ...Section 19 LPC Interface LPC Rev 1 00 Mar 12 2008 Page 756 of 1178 REJ09B0403 0100...
Страница 838: ...Section 20 Ethernet Controller EtherC Rev 1 00 Mar 12 2008 Page 790 of 1178 REJ09B0403 0100...
Страница 964: ...Section 24 RAM Rev 1 00 Mar 12 2008 Page 916 of 1178 REJ09B0403 0100...
Страница 1066: ...Section 25 Flash Memory Rev 1 00 Mar 12 2008 Page 1018 of 1178 REJ09B0403 0100...
Страница 1098: ...Section 26 Boundary Scan JTAG Rev 1 00 Mar 12 2008 Page 1050 of 1178 REJ09B0403 0100...
Страница 1168: ...Section 30 Platform Environment Control Interface PECI Rev 1 00 Mar 12 2008 Page 1120 of 1178 REJ09B0403 0100...
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Страница 1230: ...H8S 2472 Group H8S 2462 Group Hardware Manual...