H8S-2639 Datasheet, PDF (561/1547 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer

Section 13 Serial Communication Interface (SCI)
Switching from SCK Pin Function to Port Pin Function:
• Problem in Operation: When switching the SCK pin function to the output port function (high-
level output) by making the following settings while DDR = 1, DR = 1, C/A = 1, CKE1 = 0,
CKE0 = 0, and TE = 1 (synchronous mode), 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 13-27)
Half-cycle low-level output
SCK/port
Data
Bit 6
TE
C/A
1. End of transmission
Bit 7
2. TE = 0
4. Low-level output
3. C/A = 0
CKE1
CKE0
Figure 13-27 Operation when Switching from SCK Pin Function to Port Pin Function
Rev. 6.00 Feb 22, 2005 page 501 of 1484
REJ09B0103-0600