TMP88CH41UG Datasheet, PDF (151/186 Pages) Toshiba Semiconductor – 8 Bit Microcontroller

TMP88CH41UG
13.4 Transfer Rate
The baud rate of UART is set of UARTCRA<BRG>. The example of the baud rate are shown as follows.
Table 13-1 Transfer Rate (Example)
BRG
000
001
010
011
100
101
Source Clock
16 MHz
8 MHz
76800 [baud]
38400 [baud]
38400
19200
19200
9600
9600
4800
4800
2400
2400
1200
When INTTC4 is used as the UART transfer rate (when UARTCRA<BRG> = “110”), the transfer clock and trans-
fer rate are determined as follows:
Transfer clock [Hz] = TC4 source clock [Hz] / TC4DR setting value
Transfer Rate [baud] = Transfer clock [Hz] / 16
13.5 Data Sampling Method
The UART receiver keeps sampling input using the clock selected by UARTCRA<BRG> until a start bit is
detected in RXD pin input. RT clock starts detecting “L” level of the RXD pin. Once a start bit is detected, the start
bit, data bits, stop bit(s), and parity bit are sampled at three times of RT7, RT8, and RT9 during one receiver clock
interval (RT clock). (RT0 is the position where the bit supposedly starts.) Bit is determined according to majority
rule (The data are the same twice or more out of three samplings).
RXD pin
RT clock
Internal receive data
RXD pin
RT clock
Internal receive data
Start bit
Bit 0
RT0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11
Start bit
(a) Without noise rejection circuit
Bit 0
Start bit
Bit 0
RT0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11
Start bit
(b) With noise rejection circuit
Bit 0
Figure 13-4 Data Sampling Method
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