Section 28 Serial Communication Interface with FIFO/IrDA Interface (SCIF/IrDA)
Rev. 1.00 Oct. 01, 2007 Page 1178 of 1956
REJ09B0256-0100
Thus, the reception margin in asynchronous mode is given by formula (1).
1
| D - 0.5 |
M= (0.5
-
2N
) - (L - 0.5) F -
N
(1 + F)
×
100 % .................. (1)
M: Receive
margin
(%)
N: Ratio of bit rate to clock (N = 16)
D: Clock duty (D = 0 to 1.0)
L: Frame length (L = 9 to 12)
F: Absolute value of clock rate deviation
From equation (1), if F = 0 and D = 0.5, the reception margin is 46.875%, as given by formula (2).
When D = 0.5 and F = 0:
M = (0.5 – 1 / (2
×
16) )
×
100% = 46.875% ............................................... (2)
However, this is a theoretical value. A reasonable margin to allow in system designs is 20% to
30%.
(6)
Reception margin and baud rate error
The 46.875% in formula (2) is the reception margin when the baud rate error is 0 (F = 0). In other
words, reception is possible even with a misalignment of approximately half a bit if there is no
reception or transmission baud rate error. If baud rate error is present in reception or transmission,
the error accumulates until the stop bit is received, reducing the reception margin.
To calculate the allowable baud rate error, formula (1) can be modified to determine the value of
F.
If D = 0.5, the result is formula (3).
F =
{
(15/32-M) / (L – 0.5)
}
×
100 (
%
) …… Expression (3)
Based on formula (3), the relationship between the allowable baud rate error and the reception
margin when the frame length L = 12 are as follows.
Allowable baud rate error (
%
)
4.07 3.64 3.20 2.33 1.46
Reception margin (
%
) 0 5 10 20 30
Summary of Contents for SH7763
Page 2: ...Rev 1 00 Oct 01 2007 Page ii of lxvi ...
Page 122: ...Section 2 Programming Model Rev 1 00 Oct 01 2007 Page 56 of 1956 REJ09B0256 0100 ...
Page 144: ...Section 3 Instruction Set Rev 1 00 Oct 01 2007 Page 78 of 1956 REJ09B0256 0100 ...
Page 170: ...Section 4 Pipelining Rev 1 00 Oct 01 2007 Page 104 of 1956 REJ09B0256 0100 ...
Page 282: ...Section 7 Caches Rev 1 00 Oct 01 2007 Page 216 of 1956 REJ09B0256 0100 ...
Page 378: ...Section 9 Interrupt Controller INTC Rev 1 00 Oct 01 2007 Page 312 of 1956 REJ09B0256 0100 ...
Page 514: ...Section 12 DDR SDRAM Interface DDRIF Rev 1 00 Oct 01 2007 Page 448 of 1956 REJ09B0256 0100 ...
Page 630: ...Section 13 PCI Controller PCIC Rev 1 00 Oct 01 2007 Page 564 of 1956 REJ09B0256 0100 ...
Page 710: ...Section 16 Clock Pulse Generator CPG Rev 1 00 Oct 01 2007 Page 644 of 1956 REJ09B0256 0100 ...
Page 732: ...Section 17 Watchdog Timer and Reset WDT Rev 1 00 Oct 01 2007 Page 666 of 1956 REJ09B0256 0100 ...
Page 752: ...Section 18 Power Down Mode Rev 1 00 Oct 01 2007 Page 686 of 1956 REJ09B0256 0100 ...
Page 772: ...Section 19 Timer Unit TMU Rev 1 00 Oct 01 2007 Page 706 of 1956 REJ09B0256 0100 ...
Page 824: ...Section 21 Compare Match Timer CMT Rev 1 00 Oct 01 2007 Page 758 of 1956 REJ09B0256 0100 ...
Page 1124: ...Section 26 I 2 C Bus Interface IIC Rev 1 00 Oct 01 2007 Page 1058 of 1956 REJ09B0256 0100 ...
Page 1350: ...Section 30 SIM Card Module SIM Rev 1 00 Oct 01 2007 Page 1284 of 1956 REJ09B0256 0100 ...
Page 1484: ...Section 33 Audio Codec Interface HAC Rev 1 00 Oct 01 2007 Page 1418 of 1956 REJ09B0256 0100 ...
Page 1560: ...Section 35 USB Host Controller USBH Rev 1 00 Oct 01 2007 Page 1494 of 1956 REJ09B0256 0100 ...
Page 1720: ...Section 37 LCD Controller LCDC Rev 1 00 Oct 01 2007 Page 1654 of 1956 REJ09B0256 0100 ...
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Page 2026: ...SH7763 Hardware Manual ...