Cypress PSoC CY8CTMG20 Series, Technical Reference Manual

Page: 67 / 308

PSoC CY8CTMG20x and CY8CTST200 TRM, Document No. 001-53603 Rev. *C 67
8. Internal Low Speed Oscillator (ILO)
This chapter briefly explains the Internal Low Speed Oscillator (ILO) and its associated register. The Internal Low Speed
Oscillator produces a 32 kHz or 1 kHz clock. For a quick reference of all PSoC registers in address order, refer to the
Register
Reference chapter on page 187 .
8.1 Architectural Description
The Internal Low Speed Oscillator (ILO) is an oscillator with a nominal frequency of 32 kHz or 1 kHz. It is used to generate
sleep wakeup interrupts and watchdog resets. This oscillator is also used as a clocking source for the digital blocks. This
block operates with a small internal bias current and produces an output clock of either 1 kHz or 32 kHz, configurable by the
user. The ILO is trimmed for 32 kHz in production devices. There is no trim for 1 kHz, hence, high variation is expected from
nominal value.
The block operates by charging a capacitor with a current, to a reference level. Once reached, the capacitor is discharged to
ground. This process repeats to provide the oscillator (half) period.
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