User's Manual

Table Of Contents
S3C2450X RISC MICROPROCESSOR HSMMC CONTROLLER
21-5
4.3 SD CLOCK STOP SEQUENCE
START
Set SD Clock OFF
END
(1)
Stop SD Clock
Figure 21-4. SD Clock Stop Sequence
The flow chart for stopping the SD Clock is shown in Figure 21-4. The Host Driver shall not stop the SD Clock
when a SD transaction is occurring on the SD Bus -- namely, when either Command Inhibit (DAT) or Command
Inhibit (CMD) in the Present State register is set to 1.
(1) Set SD Clock Enable(ENSDCLK) in the Clock Control register to 0. Then, the Host Controller stops supplying
the SD Clock.
4.4 SD CLOCK FREQUENCY CHANGE SEQUENCE
START
SD Clock Stop
SD Clock Supply
END
(1)
(2)
Figure 21-5. SD Clock Change Sequence
The sequence for changing SD Clock frequency is shown in Figure 21-5. When SD Clock is still off, step (1) is
omitted.