3069RF-ZTAT Datasheet, PDF (534/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

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 13.23)
Half-cycle low-level output
SCK/port
Data
Bit 6
TE
C/)
1. End of transmission
Bit 7
2. TE= 0
4. Low-level output
3. C/)= 0
CKE1
CKE0
Figure 13.23 Operation when Switching from SCK Pin Function to Port Pin Function
Rev. 5.0, 09/04, page 512 of 978