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Chapter 16
Asynchronous Serial Interface (UARTA)
Preliminary User’s Manual U17566EE1V2UM00
16.6.7
Baud rate during continuous transmission
During continuous transmission, the transfer rate from the stop bit to the next
start bit is usually 2 base clocks longer. However, timing initialization is
performed via start bit detection by the receiving side, so this has no influence
on the transfer result.
Figure 16-13
Transfer rate during continuous transfer
Assuming 1 bit data length: FL; stop bit length: FLstp; and base clock
frequency: f
UCLK
, we obtain the following equation.
FLstp = FL + 2/f
UCLK
Therefore, the transfer rate during continuous transmission is as follows.
Transfer rate = 11
×
FL + (2/f
UCLK
)
16.7 Cautions
• When the clock supply to UARTAn is stopped (for example, in IDLE or STOP
mode), the operation stops with each register retaining the value it had
immediately before the clock supply was stopped. The TXDAn pin output
also holds and outputs the value it had immediately before the clock supply
was stopped. However, the operation is not guaranteed after the clock
supply is resumed. Therefore, after the clock supply is resumed, the circuits
should be initialized by setting the UAnCTL0.UAnPWR,
UAnCTL0.UAnRXEn, and UAnCTL0.UAnTXEn bits to 000.
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