Section 16 Serial Communication Interface (SCI, IrDA, and CRC)
Rev. 3.00 Jan 25, 2006 page 405 of 872
REJ09B0286-0300
16.3.9
Bit Rate Register (BRR)
BRR is an 8-bit register that adjusts the bit rate. As the SCI performs baud rate generator control
independently for each channel, different bit rates can be set for each channel. Table 16.2 shows
the relationships between the N setting in BRR and bit rate B for normal asynchronous mode and
clocked synchronous mode, and smart card interface mode. The initial value of BRR is H'FF, and
it can be read from or written to by the CPU at all times.
Table 16.2 Relationships between N Setting in BRR and Bit Rate B
Mode
Bit Rate
Error
Asynchronous
mode
B =
64
×
2
2n–1
×
(N + 1)
φ ×
10
6
B
×
64
×
2
2n–1
×
(N + 1)
φ ×
10
6
Error (%) =
{
}
– 1
×
100
Clocked
synchronous
mode
B =
—
Smart card
interface mode
B =
Error (%) =
B
×
S
×
2
2n+1
×
(N + 1)
φ ×
10
6
{
}
– 1
×
100
8
×
2
2n–1
×
(N + 1)
φ ×
10
6
S
×
2
2n+1
×
(N + 1)
φ ×
10
6
Notes: B: Bit rate (bit/s)
N: BRR setting for baud rate generator (0
≤
N
≤
255)
φ
: Operating frequency (MHz)
n and S: Determined by the SMR settings shown in the following table.
SMR Setting
SMR Setting
CKS1
CKS0
n
BCP1
BCP0
S
0
0
0
0
0
32
0
1
1
0
1
64
1
0
2
1
0
372
1
1
3
1
1
256
Table 16.3 shows sample N settings in BRR in normal asynchronous mode. Table 16.4 shows the
maximum bit rate settable for each frequency. Table 16.6 shows sample N settings in BRR in
clocked synchronous mode, and table 16.8 shows sample N settings in BRR in smart card
interface mode. In smart card interface mode, the number of basic clock cycles S in a 1-bit data
transfer time can be selected. For details, see section 16.7.4, Receive Data Sampling Timing and
Reception Margin. Tables 16.5 and 16.7 show the maximum bit rates with external clock input.
Summary of Contents for H8S/2158
Page 10: ...Rev 3 00 Jan 25 2006 page viii of lii...
Page 36: ...Rev 3 00 Jan 25 2006 page xxxiv of lii B Product Lineup 863 C Package Dimensions 864 Index 865...
Page 47: ...Rev 3 00 Jan 25 2006 page xlv of lii Appendix Figure C 1 Package Dimensions TBP 112A 864...
Page 54: ...Rev 3 00 Jan 25 2006 page lii of lii...
Page 70: ...Section 1 Overview Rev 3 00 Jan 25 2006 page 16 of 872 REJ09B0286 0300...
Page 118: ...Section 3 MCU Operating Modes Rev 3 00 Jan 25 2006 page 64 of 872 REJ09B0286 0300...
Page 126: ...Section 4 Exception Handling Rev 3 00 Jan 25 2006 page 72 of 872 REJ09B0286 0300...
Page 198: ...Section 6 Bus Controller Rev 3 00 Jan 25 2006 page 144 of 872 REJ09B0286 0300...
Page 326: ...Section 10 8 Bit PWM Timer PWM Rev 3 00 Jan 25 2006 page 272 of 872 REJ09B0286 0300...
Page 440: ...Section 15 Watchdog Timer WDT Rev 3 00 Jan 25 2006 page 386 of 872 REJ09B0286 0300...
Page 606: ...Section 17 I 2 C Bus Interface IIC Rev 3 00 Jan 25 2006 page 552 of 872 REJ09B0286 0300...
Page 742: ...Section 19 Multimedia Card Interface MCIF Rev 3 00 Jan 25 2006 page 688 of 872 REJ09B0286 0300...
Page 750: ...Section 21 D A Converter Rev 3 00 Jan 25 2006 page 696 of 872 REJ09B0286 0300...
Page 768: ...Section 22 A D Converter Rev 3 00 Jan 25 2006 page 714 of 872 REJ09B0286 0300...
Page 770: ...Section 23 RAM Rev 3 00 Jan 25 2006 page 716 of 872 REJ09B0286 0300...
Page 824: ...Section 26 Clock Pulse Generator Rev 3 00 Jan 25 2006 page 770 of 872 REJ09B0286 0300...
Page 844: ...Section 27 Power Down Modes Rev 3 00 Jan 25 2006 page 790 of 872 REJ09B0286 0300...
Page 878: ...Section 28 List of Registers Rev 3 00 Jan 25 2006 page 824 of 872 REJ09B0286 0300...
Page 926: ...Index Rev 3 00 Jan 25 2006 page 872 of 872 REJ09B0286 0300...