8. Clock generator
A96G140/A96G148/A96A148 User’s manual
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8
Clock generator
As shown in figure 24, a clock generator produces basic clock pulses which provide a system clock for
CPU and peripheral hardware.
It contains main/sub-frequency clock oscillator. The main/sub clock can operate easily by attaching a
crystal between the XIN/SXIN and XOUT/SXOUT pin, respectively. The main/sub clock can be also
obtained from the external oscillator. For this, it is necessary to place external clock signal into the
XIN/SXIN pin and open XOUT/SXOUT pin.
Default system clock is 1MHz INT-RC Oscillator. To stabilize the system internally, 128KHz LOW INT-
RC oscillator on POR is recommended.
Oscillators in the clock generator are introduced in the followings:
Calibrated high internal RC oscillator (32MHz)
—
HSIRC OSC/2 (16MHz, default system clock)
—
HSIRC OSC/4 (8MHz)
—
HSIRC OSC/8 (4MHz)
—
HSIRC OSC/16 (2MHz)
—
HSIRC OSC/32 (1MHz)
—
HSIRC OSC/64 (0.5MHz)
Main crystal oscillator (4~12MHz)
Sub-crystal Oscillator (32.768kHz)
Internal LSIRC oscillator (128kHz)
8.1
Clock generator block diagram
In this section, a clock generator of A96G140/A96G148/A96A148 is described in a block diagram.