Switching From Sck Pins To Port Pins; Figure 16.25 Switching From Sck Pins To Port Pins; Figure 16.26 Prevention Of Low Pulse Output At Switching From Sck Pins To Port Pins - Renesas H8S/2437 Hardware Manual

16.8.7

Switching from SCK Pins to Port Pins

When SCK pins are switched to port pins after transmission has completed, pins are enabled for
port output after outputting a low pulse of half a cycle as shown in figure 16.25.
SCK/Port
Bit 6
Data
TE
C/
CKE1
CKE0
To prevent the low pulse output that is generated when switching the SCK pins to the port pins,
specify the SCK pins for input (pull up the SCK/port pins externally), and follow the procedure
below with DDR = 1, DR = 1, C/A = 1, CKE1 = 0, CKE0 = 0, and TE = 1.
1. End serial data transmission
2. TE bit = 0
3. CKE1 bit = 1
4. C/A bit = 0 (switch to port output)
5. CKE1 bit = 0
SCK/Port
Data
Bit 6
TE
C/
CKE1
CKE0

Figure 16.26 Prevention of Low Pulse Output at Switching from SCK Pins to Port Pins

1. Transmission end
Bit 7
2. TE = 0

Figure 16.25 Switching from SCK Pins to Port Pins

1. Transmission end
Bit 7
2. TE = 0
Low pulse of half a cycle
4. Low pulse output
3. C/ = 0
4. C/ = 0
3. CKE1 = 1
Rev. 1.00, 09/03, page 473 of 704
High output
5. CKE1 = 0