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16. Asynchronous Serial Interface (UART)
16.8 Transfer Baud Rate
TMP89FM42
RA001
Note 1: The overall error from the basic baud rate must be within
±
3%. Even if the overall error is within
±
3%, the commu-
nication may fail due to factors such as frequency errors in external controllers (for example, a personal computer)
and oscillators and the load capacity of the communication pin.
16.8.1 Transfer baud rate calculation method
16.8.1.1 Bit width adjustment using UART0CR2<RTSEL>
The bit width of transmitted/received data can be finely adjusted by changing UART0CR2<RTSEL>.
The number of RT clocks per bit can be changed in a range of 15 to 17 clocks by changing
UART0CR2<RTSEL>. The RT clock is the transfer base clock, which is the pulses obtained by counting
the clock selected at UART0CR1<BRG> the number of times of (UART0DR set value) + 1. Especially,
when UART0CR2<RTSEL> is set to "0y001" or "0y011", two types of RT clocks alternate at each bit, so
that the pseudo baud rates of RT
×
15.5 clocks and RT
×
16.5 clocks can be generated. The number of RT
clocks per bit of transfer frame is shown in Figure 16-4.
For example, when fcgck is 4 [MHz], UART0CR2<RTSEL> is set to "0y000" and UART0DR is set to
"0x19", the baud rate calculated using the formula in Figure 16-4 is expressed as:
fcgck / (16
×
(U 1) = 9615 [baud]
These settings generate a baud rate close to 9600 [baud] (+0.16%).
Table 16-7 Set Values of UART0DR and UART0CR2<RTSEL> for Transfer
Baud Rates (fs=32.768 kHz, UART0CR2<RXDNC>=0y00)
Basic baud
rate
[baud]
Register
Operating frequency
32.768 kHz
300
UART0DR
0x06
RTSEL
0y011
Error
(+0.67%)
150
UART0DR
0x0D
RTSEL
0y011
Error
(+0.67%)
134
UART0DR
0x0E
RTSEL
0y001
Error
(-1.20%)
110
UART0DR
0x11
RTSEL
0y001
Error
(+0.30%)
75
UART0DR
0x1C
RTSEL
0y010
Error
(+0.44%)
Summary of Contents for TLCS-870/C1 Series
Page 1: ...8 Bit Microcontroller TLCS 870 C1 Series TMP89FM42 查询TMP89FM42供应商 捷多邦 专业PCB打样工厂 24小时加急出货 ...
Page 3: ...Revision History Date Revision 2007 10 25 1 First Release 2007 11 3 2 Contents Revised ...
Page 4: ......
Page 14: ......
Page 18: ...1 3 Block Diagram TMP89FM42 1 3 Block Diagram Figure 1 2 Block Diagram ...
Page 22: ...1 4 Pin Names and Functions TMP89FM42 ...
Page 60: ...2 CPU Core 2 5 Revision History TMP89FM42 ...
Page 76: ...3 Interrupt Control Circuit 3 8 Revision History TMP89FM42 ...
Page 86: ...4 External Interrupt control circuit 4 3 Function TMP89FM42 ...
Page 102: ...7 Voltage Detection Circuit 7 5 Revision History TMP89FM42 ...
Page 126: ...8 I O Ports 8 3 I O Port Registers TMP89FM42 Note 2 i 0 to 1 ...
Page 136: ...8 I O Ports 8 5 Revision History TMP89FM42 ...
Page 142: ...9 Special Function Registers 9 3 SFR3 0x0E40 to 0x0EFF TMP89FM42 ...
Page 146: ...10 Low Power Consumption Function for Peripherals TMP89FM42 ...
Page 149: ...TMP89FM42 11 3 Revision History Rev Description RA001 Deleted SLEEP2 description ...
Page 150: ...11 Divider Output DVO 11 3 Revision History TMP89FM42 ...
Page 220: ...15 Real Time Clock RTC 15 4 Real Time Clock Operation TMP89FM42 ...
Page 250: ...16 Asynchronous Serial Interface UART 16 15 Revision History TMP89FM42 ...
Page 302: ...18 Serial Bus Interface SBI 18 7 Revision History TMP89FM42 ...
Page 338: ...21 Flash Memory 21 4 Toggle Bit D6 TMP89FM42 ...
Page 384: ...22 Serial PROM Mode 22 15 Revision History TMP89FM42 ...
Page 388: ...24 Input Output Circuit 24 1 Control Pins TMP89FM42 ...
Page 404: ...25 Electrical Characteristics 25 11 Revision History TMP89FM42 ...
Page 406: ...26 Package Dimensions TMP89FM42 ...
Page 408: ......