h8s-2628 Renesas Electronics Corporation., h8s-2628 Datasheet - Page 406

• Manufacturer Part Number: h8s-2628
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 14 Serial Communication Interface (SCI)
14.7.8
When the GM bit in SMR is set to 1, the clock output level can be fixed with bits CKE0 and
CKE1 in SCR. At this time, the minimum clock pulse width can be made the specified width.
Figure 14.31 shows the timing for fixing the clock output level. In this example, GM is set to 1,
CKE1 is cleared to 0, and the CKE0 bit is controlled.
When turning on the power or switching between Smart Card interface mode and software standby
mode, the following procedures should be followed in order to maintain the clock duty cycle.
Powering On: To secure clock duty cycle from power-on, the following switching procedure
should be followed.
Rev. 3.00 Oct 04, 2005 page 366 of 598
REJ09B0155-0300
1. The initial state is port input and high impedance. Use a pull-up resistor or pull-down
2. Fix the SCK pin to the specified output level with the CKE1 bit in SCR.
3. Set SMR and SCMR, and switch to smart card mode operation.
4. Set the CKE0 bit in SCR to 1 to start clock output.
CKE0
SCK
resistor to fix the potential.
Clock Output Control
Figure 14.31 Timing for Fixing Clock Output Level
Specified pulse width
Specified pulse width