HD64F2636F20 Datasheet, PDF (1026/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 23B Power-Down Modes [HD64F2636UF, HD6432636UF, HD64F2638UF, HD6432638UF,
HD64F2638WF, HD6432638WF, HD64F2639UF, HD6432639UF, HD64F2639WF, HD6432639WF,
HD64F2630UF, HD6432630UF, HD64F2630WF, HD6432630WF, HD6432635F, HD64F2635F, HD6432634F]
H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
23B.12 φ Clock Output Disabling Function
Output of the φ clock can be controlled by means of the PSTOP bit in SCKCR, and DDR for the
corresponding port. When the PSTOP bit is set to 1, the φ clock stops at the end of the bus cycle,
and φ output goes high. φ clock output is enabled when the PSTOP bit is cleared to 0. When DDR
for the corresponding port is cleared to 0, φ clock output is disabled and input port mode is set.
Table 23B-8 shows the state of the φ pin in each processing state.
Using the on-chip PLL circuit to lower the oscillator frequency or prohibiting external φ clock
output also have the effect of reducing unwanted electromagnetic interference*. Therefore,
consideration should be given to these options when deciding on system board settings.
Note: * Electromagnetic interference: EMI (Electro Magnetic Interference)
Table 23B-8 φ Pin State in Each Processing State
DDR
0
1
1
PSTOP
—
0
1
Hardware standby mode
High impedance High impedance High impedance
Software standby mode, watch
mode^*, and direct transition
Sleep mode and subsleep mode^*
High impedance
High impedance
Fixed high
φ output
Fixed high
Fixed high
High-speed mode, medium-speed High impedance
mode, and subactive mode^*
φ output
Fixed high
Subactive mode
High impedance φ SUB output
Fixed high
Note: * Subclock functions (subactive mode, subsleep mode, and watch mode) are available in the
U-mask and W-mask versions, and H8S/2635 Group only.
These functions cannot be used with the other versions.
Page 976 of 1458
REJ09B0103-0800 Rev. 8.00
May 28, 2010