Notes When Switching From Sck Pin To Port Pin; Figure 14.37 Sample Flowchart For Mode Transition During Reception - Renesas H8S Series Hardware Manual

Section 14 Serial Communication Interface (SCI)
Read RDRF flag in SSR
Read receive data in RDR
Make transition to software standby mode etc.
Cancel software standby mode etc.
Change operating mode?

Figure 14.37 Sample Flowchart for Mode Transition during Reception

14.9.7

Notes when Switching from SCK Pin to Port Pin

• Problem in Operation: When DDR and DR are set to 1, SCI clock output is used in clocked
synchronous mode, and the SCK pin is changed to the port pin while transmission is ended,
port output is enabled after low-level output occurs for one half-cycle.
When switching the SCK pin to the port pin by making the following settings while DDR = 1,
DR = 1, C/A = 1, CKE1 = 0, CKE0 = 0, and TE = 1, low-level output occurs for one half-
cycle.
1. End of serial data transmission
2. TE bit = 0
3. C/A bit = 0 ... switchover to port output
4. Occurrence of low-level output (see figure 14.38)
Rev. 6.00 Mar 15, 2006 page 382 of 570
REJ09B0211-0600
Reception
No
RDRF = 1
Yes
RE = 0
No
Yes
Initialization
Start reception
[1] [1] Data being received will be invalid.
[2] Module stop, watch, sub-active, and sub-
sleep modes are included.
[2]
RE = 1