h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 508

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 15 Serial Communication Interface (SCI, IrDA)
Restrictions on Use of DTC
Rev. 4.00 Jun 06, 2006 page 454 of 1004
REJ09B0301-0400
When an external clock source is used as the serial clock, the transmit clock should not be
input until at least 5 clock cycles after TDR is updated by the DTC. Misoperation may occur
if the transmit clock is input within 4 clock cycles after TDR is updated. (Figure 15.24)
When RDR is read by the DTC, be sure to set the activation source to the relevant SCI receive-
data-full interrupt (RXI).
SCK
TDRE
Serial data
Note: When operating on an external clock, set t > 4 states.
Figure 15.24 Example of Synchronous Transmission by DTC
t
LSB
D0
D1
D2
D3
D4
D5
D6
D7