DS508UM1
21
(i.e. the supply voltage level used to drive all of the non-V
DD
core pins on the EP7312). The output clock
pin (i.e., MOSCOUT) should be left floating.
2.5.2
External Clock Input (13 MHz)
An external 13 MHz crystal oscillator can be used to drive all of the EP7312. When selected the ARM720T
and the address/data buses both get clocked at 13 MHz. The fixed clock sources to the various peripherals
will have different frequencies than in the PLL mode. In this configuration, the PLL will not be used at all.
Note:
When operating at 13 MHz, the CLKCTL[1:0] bits should not be changed from their default value of “00.”
Figure 3. CLKEN Timing Entering the Standby State
13 MHz
CLKEN
EXPCLK
(internal)
RUN
Interrupt /
WAKEUP
CLKEN
Figure 4. CLKEN Timing Exiting the Standby State
Summary of Contents for EP7312
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