
ML62Q1000 Series User's Manual
Chapter 11 Serial Communication Unit
FEUL62Q1000
11-46
11.3.2.2 Baud Rate
The baud rate generator generates a baud rate using the base clock chosen in the UARTn mode register (UAn0MOD and
UAn1MOD). The setting values for the UARTn baud rate register (UAn0BRT and UAn1BRT) and the UARTn baud rate
adjustment register (UAn0BRC and UAn1BRC) can be calculated by the following formulae.
UAn0BRT = Base clock frequency (Hz) / Baud rate (bps) - 1
UAn0BRC = Base clock frequency (Hz) % Baud rate (bps) x 8 / Baud rate (bps)
For ML62Q1700 group, when the CPU operation clock is set to 24 MHz, the setting values are usually calculated
assuming that the base clock frequency for calculation of the UART baud rate is 23.986176 MHz (15.990784 MHz when
16 MHz). This value is "the central value set for built-in oscil PLL oscillation". An error of each LSI unit can be
minimized by measuring the frequency for each LSI unit and adjusting it to align with the central value.
Example: Base clock frequency: Approx.24 MHz (23.986176 MHz), Baud rate: 115,200 bps
UAn0BRT = 23.986176 MHz / 115,200 bps
−
1
= 208.21333…
−
1 = 207 (rounding down to the nearest integer)
= 0x00CF
UAn0BRC = (23.986176 MHz % 115,200 bps) x 8 / Baud rate (bps)
= (24576 x 8) / 115,200
= 196608 / 115,200
= 1.70666… = 2 (rounding to the nearest integer)
= 0x02
The actual baud rate calculated from the setting value for the baud rate can be expressed by the following formula:
Actual baud rate (bps) = [Base clock frequency] / {( 1) + (UAn0BRC / 8)}
Example: Base clock frequency: Approx.24 MHz (23.986176 MHz), Baud rate ideal value: 1200 bps
Actual baud rate (bps) = 23.986176 MHz / {( 1)} + (0x04 / 8)}
≈ 1199.99
Table 11-7 lists the count values for typical baud rates.
Table 11-7 Count Values for Typical Baud Rates (1/2)
Base clock
Baud rate
UAn0BRT
UAn1BRT
UAn0BRC
UAn1BRC
Actual
baud rate
Approx. 24 MHz
(approx. 23.986176 MHz)
1,200bps
0x4E13
0x04
1199.99bps
2,400bps
0x2709
0x02
2399.99bps
4,800bps
0x1384
0x01
4799.99bps
9,600bps
0x09C1
0x04
9600.23bps
19,200bps
0x04E0
0x02
19200.46bps
38,400bps
0x026F
0x05
38400.92bps
57,600bps
0x019F
0x03
57607.14bps
115,200bps
0x00CF
0x02
115179.71bps
Содержание ML62Q1000 Series
Страница 17: ...Chapter 1 Overview...
Страница 112: ...Chapter 2 CPU and Memory Space...
Страница 154: ...Chapter 3 Reset Function...
Страница 166: ...Chapter 4 Power Management...
Страница 196: ...Chapter 5 Interrupts...
Страница 248: ...Chapter 6 Clock generation Circuit...
Страница 274: ...Chapter 7 Low Speed Time Base Counter...
Страница 291: ...Chapter 8 16 Bit Timer...
Страница 320: ...Chapter 9 Functional Timer FTM...
Страница 382: ...Chapter 10 Watchdog Timer...
Страница 402: ...Chapter 11 Serial Communication Unit...
Страница 456: ...Chapter 12 I2 C Bus Unit...
Страница 491: ...Chapter 13 I2 C Master...
Страница 512: ...Chapter 14 DMA Controller...
Страница 531: ...Chapter 15 Buzzer...
Страница 550: ...Chapter 16 Simplified RTC...
Страница 559: ...Chapter 17 GPIO...
Страница 594: ...Chapter 18 External Interrupt Function...
Страница 612: ...Chapter 19 CRC Generator...
Страница 632: ...Chapter 20 Analog Comparator...
Страница 644: ...Chapter 21 D A Converter...
Страница 655: ...Chapter 22 Voltage Level Supervisor...
Страница 676: ...Chapter 23 Successive Approximation Type A D Converter...
Страница 709: ...Chapter 24 Regulator...
Страница 714: ...Chapter 25 Flash Memory...
Страница 743: ...Chapter 26 Code Option...
Страница 750: ...Chapter 27 LCD Driver...
Страница 788: ...Chapter 28 On Chip Debug Function...
Страница 795: ...Chapter 29 Safety Function...
Страница 813: ...Appendix A...
Страница 881: ...Revision History...