Datasheet

78K0/Ix2 CHAPTER 14 SERIAL INTERFACE UART6/DALI
R01UH0010EJ0500 Rev.5.00 469
Feb 28, 2012
14.4.5 Calculation of baud rate
(1)
Baud rate calculation expression
The baud rate can be calculated by the following expression.
 UART mode: Baud rate = [bps]
 DALI mode: Baud rate = [bps]
f
XCLK6: Frequency of base clock selected by TPS63 to TPS60 bits of CKSR6 register
k: Value set by MDL67 to MDL60 bits of BRGC6 register (UART mode: k = 4, 5, 6, ..., 255, DALI mode: k = 8, 9,
10, ..., 255)
Table 14-5. Set Value of TPS63 to TPS60
Base clock (fXCLK6) selection TPS63 TPS62 TPS61 TPS60
f
PRS =
2 MHz
fPRS =
5 MHz
fPRS =
10 MHz
fPRS =
20 MHz
(when
using PLL)
0 0 0 0 fPRS 2 MHz 5 MHz 10 MHz 20 MHz
0 0 0 1 fPRS/2 1 MHz 2.5 MHz 5 MHz 10 MHz
0 0 1 0 fPRS/2
2
500 kHz 1.25 MHz 2.5 MHz 5 MHz
0 0 1 1 fPRS/2
3
250 kHz 625 kHz 1.25 MHz 2.5 MHz
0 1 0 0 fPRS/2
4
125 kHz 312.5 kHz 625 kHz 1.25 MHz
0 1 0 1 fPRS/2
5
62.5 kHz 156.25 kHz 312.5 kHz 625 kHz
0 1 1 0 fPRS/2
6
31.25 kHz 78.13 kHz 156.25 kHz 312.5 kHz
0 1 1 1 fPRS/2
7
15.625 kHz 39.06 kHz 78.13 kHz 156.25 kHz
1 0 0 0 fPRS/2
8
7.813 kHz 19.53 kHz 39.06 kHz 78.13 kHz
1 0 0 1 fPRS/2
9
3.906 kHz 9.77 kHz 19.53 kHz 39.06 kHz
1 0 1 0
f
PRS/2
1
0
1.953 kHz 4.88 kHz 9.77 kHz 19.53 kHz
Other than above Setting prohibited
(2) Error of baud rate
The baud rate error can be calculated by the following expression.
 Error (%) =  1  100 [%]
Cautions 1. Keep the baud rate error during transmission to within the permissible error range at the
reception destination.
2. Make sure that the baud rate error during reception satisfies the range shown in (4) Permissible
baud rate range during reception.
f
XCLK6
2  k
Actual baud rate (baud rate with error)
Desired baud rate (correct baud rate)
fXCLK6
4  k