Reception In Uart Mode - Renesas M16C Series User Manual

M30240 Group

2.5.2.2 Reception in UART mode

For receiving data in UART mode, select functions from those listed in Table 2.21 . An example using
the indicated options is described below. Figure 2.65 shows the operation timing, and Figure 2.66 and
Figure 2.67 show the set-up procedures.
Table 2.21: Serial I/O reception in UART mode functions
Item
Transfer clock source
(Note 1)
O
O
RTS function
O
Sleep mode (Note 1)
Note 1: UART0, UART1 only
Note 2: UART2 only
Operation
(1) Setting the receive enable bit to "1" readies data-receivable status. At this time, output from the
RTSi pin goes to "L" level to inform the transmission side that the receivable status is ready.
(2) When the first bit (the start bit) of reception data is received from the RxDi pin, output from the RTS
goes to "H" level. Then, data is received, bit by bit, in sequence: LSB to MSB, and stop bit(s).
(3) When the stop bit(s) is (are) received, the content of the UARTi receive register is transmitted to
the UARTi receive buffer register.
At this time, the receive complete flag goes to "1" to indicate that the reception is completed, the UARTi
receive interrupt request bit goes to "1", and output from the RTS pin goes to "L" level.
(4) The receive complete flag goes to "0" when the lower-order byte of the UARTi buffer register is
read.
Rev.1.00 Sep 24, 2003 Page 214 of 360
Set-up
Internal clock (f1/f8/f32)
External clock (CLKi pin)
RTS function enabled
RTS function disabled
Sleep mode off
Sleep mode on
Clock-Asynchronous Serial I/O
Item
O
Data logic select function
(Note 2)
O
TxD, RxD I/O polarity
reverse bit (Note 2)
O
Bus collision detection
function (Note 2)
Set-up
No reverse
Reverse
No reverse
Reverse
Not selected
Selected