CY8C36_12 Datasheet, PDF (26/131 Pages) Cypress Semiconductor – Programmable System-on-Chip (PSoC®)

PSoC^® 3: CY8C36 Family
Data Sheet
6. System Integration
6.1 Clocking System
The clocking system generates, divides, and distributes clocks
throughout the PSoC system. For the majority of systems, no
external crystal is required. The IMO and PLL together can
generate up to a 66 MHz clock, accurate to ±1% over voltage and
temperature. Additional internal and external clock sources allow
each design to optimize accuracy, power, and cost. Any of the
clock sources can be used to generate other clock frequencies
in the 16-bit clock dividers and UDBs for anything the user wants,
for example a UART baud rate generator.
Clock generation and distribution is automatically configured
through the PSoC Creator IDE graphical interface. This is based
on the complete system’s requirements. It greatly speeds the
design process. PSoC Creator allows you to build clocking
systems with minimal input. You can specify desired clock
frequencies and accuracies, and the software locates or builds a
clock that meets the required specifications. This is possible
because of the programmability inherent in PSoC.
Key features of the clocking system include:
 Seven general purpose clock sources
 3- to 62-MHz IMO, ±1% at 3 MHz
 4- to 25-MHz external crystal oscillator (MHzECO)
 Clock doubler provides a doubled clock frequency output for
the USB block, see USB Clock Domain on page 29.
 DSI signal from an external I/O pin or other logic
 24- to 67-MHz fractional PLL sourced from IMO, MHzECO,
or DSI
 1-kHz, 33-kHz, 100-kHz ILO for WDT and sleep timer
 32.768-kHz external crystal oscillator (kHzECO) for RTC
 IMO has a USB mode that auto locks to the USB bus clock
requiring no external crystal for USB. (USB equipped parts only)
 Independently sourced clock in all clock dividers
 Eight 16-bit clock dividers for the digital system
 Four 16-bit clock dividers for the analog system
 Dedicated 16-bit divider for the bus clock
 Dedicated 4-bit divider for the CPU clock
 Automatic clock configuration in PSoC Creator
Document Number: 001-53413 Rev. *O
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