CHAPTER 10 SERIAL INTERFACE UART6
Preliminary User’s Manual U19014EJ1V0UD
253
10.5 Cautions for Serial Interface UART6
(1) Data frame length during continuous transmission
When data is continuously transmitted, the data frame length from a stop bit to the next start bit is extended by
two clocks of base clock from the normal value. However, the result of communication is not affected because
the timing is initialized on the reception side when the start bit is detected.
Figure 10-19. Data Frame Length During Continuous Transmission
Start bit
Bit 0
Bit 1
Bit 7
Parity bit
Stop bit
FL
1 data frame
FL
FL
FL
FL
FL
FL
FLstp
Start bit of
second byte
Start bit
Bit 0
Where the 1-bit data length is FL, the stop bit length is FLstp, and base clock frequency is f
XCLK6
, the following
expression is satisfied.
FLstp = FL + 2/f
XCLK6
Therefore, the data frame length during continuous transmission is:
Data frame length = 11
×
FL + 2/f
XCLK6
(2) Operating current in STOP mode
The UART6 operation is stopped in the STOP mode. At this time, the operating current can be reduced by
clearing bits 7 (POWER6), 6 (TXE6), and 5 (RXE6) of the asynchronous serial interface operation mode register
(ASIM6) to 0.
To resume the operation from the standby status, first clear bit 7 (POWER6) of interrupt request flag register 0L
(IF0L), bits 1 (STIF6) and 0 (SRIF6) of interrupt request flag register 0H (IF0H) to 1, and then start operation.
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