HD6417320 RENESAS [Renesas Technology Corp], HD6417320 Datasheet - Page 1115

• Manufacturer Part Number: HD6417320
• Description: Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

31.3.15 Transfer Clock Control Register (CLKON)
CLKON controls the transfer clock frequency and clock on/off.
The 33-MHz peripheral clock is needed, and bits CSEL3 to CSEL0 should be set to 0001 for a
16.5-Mbps transfer clock of the MMCIF. At this time, transfer should be performed by sufficiently
slow transfer clock in the open drain state.
In the command sequence, do not perform clock on/off or frequency modification.
Note: The maximum operating frequency of the peripheral clock is 33.34 MHz.
Bit
7
6 to 4
3
2
1
0
Bit Name
CLKON
—
CSEL3
CSEL2
CSEL1
CSEL0
Initial
Value
0
All 0
0
0
0
0
R
R/W
R/W
R/W
R/W
R/W
R/W
Description
Clock On
0: Stops the transfer clock output from the CLK/SCLK
1: Outputs the transfer clock from the CLK/SCLK pin.
Reserved
These bits are always read as 0. The write value should
always be 0.
Transfer Clock Frequency Select
0000: Setting prohibited
0001: Uses the 1/2-divided peripheral clock as a transfer
0010: Uses the 1/4-divided peripheral clock as a transfer
0011: Uses the 1/8-divided peripheral clock as a transfer
0100: Uses the 1/16-divided peripheral clock as a
0101: Uses the 1/32-divided peripheral clock as a
0110: Uses the 1/64-divided peripheral clock as a
0111: Uses the 1/128-divided peripheral clock as a
1000: Uses the 1/256-divided peripheral clock as a
1001 to 1111: Setting prohibited
pin.
clock.
clock.
clock.
transfer clock.
transfer clock.
transfer clock.
transfer clock.
transfer clock.
Section 31
Rev. 3.00 Jan. 18, 2008 Page 1053 of 1458
MultiMediaCard Interface (MMCIF)
REJ09B0033-0300