H83802 Datasheet, PDF (326/555 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 10 Serial Communication Interface 3 (SCI3)
10.4.1 Clock
Either an internal clock generated by the on-chip baud rate generator or an external clock input at
the SCK32 pin can be selected as the SCI3’s serial clock source, according to the setting of the
COM bit in SMR and the CKE0 and CKE1 bits in SCR3. For details on selection of the clock
source, see table 10.9. When an external clock is input at the SCK32 pin, the clock frequency
should be 16 times the bit rate used. When the SCI3 is operated on an internal clock, the clock can
be output from the SCK32 pin. The frequency of the clock output in this case is equal to the bit
rate, and the phase is such that the rising edge of the clock is in the middle of the transmit data, as
shown in figure 10.3.
Clock
Serial data
0 D0 D1 D2 D3 D4 D5 D6 D7 0/1 1 1
1 character (frame)
Figure 10.3 Relationship between Output Clock and Transfer Data Phase
(Asynchronous Mode) (Example with 8-Bit Data, Parity, Two Stop Bits)
Rev. 6.00 Mar 15, 2005 page 276 of 502
REJ09B0024-0600