
CybraTech (2000) Ltd.
SOC-3000/i Scale-On-Chip
ASIC
Technical Specification
Revision B
Page 55
July, 2002
PROGRAMMABLE FREQUENCY CONTROLLER
Features
• Programmable CPU clock frequency: 16, 8, 4,
2, 1 or 0.5 MHz
• Driven by a 16-MHz resonator or crystal
oscillator
Functions
• Generates independent clocks for the CPU and
controllers (ADC converter, display,
keyboard, watchdog timer, etc.)
Clock Generator Block Diagram
The clock generator block diagram is presented in
Figure 24.
Functional Description
Dividing the 16-MHz frequency source according
to the control register setting generates the CPU
clock frequency.
The CPU clock can be set to 16, 8, 4, 2, 1 or
0.5 MHz.
Switching CPU frequency:
• To switch from the 16-MHz frequency to any
other frequency, program the frequency-
controller control register as shown in
Table 28.
• To switch from any frequency (other than
16 MHz) to another frequency, first switch to
16 MHz and then switch to the desired
frequency.
16 MHz
Clock
16 MHz (Default)
1/2
8 MHz
1/2
4 MHz
1/2
2 MHz
1/2
1 MHz
1/2
0.5 MHz
FIGURE 24: CLOCK GENERATOR BLOCK DIAGRAM