An oscillator start-up timer (OST) is a module used by some
microcontroller
A microcontroller (MC, uC, or μC) or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Pro ...
s to keep the device reset until the
crystal oscillator
A crystal oscillator is an electronic oscillator Electrical circuit, circuit that uses a piezoelectricity, piezoelectric crystal as a frequency selective surface, frequency-selective element. The oscillator frequency is often used to keep trac ...
is stable. When a crystal oscillator starts up, its frequency is not constant, which causes the
clock
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...
frequency to be non-constant. This would cause timing errors, leading to many problems. An oscillator start-up timer ensures that the device only operates when the oscillator generates a stable clock frequency.
The
PIC microcontroller
PIC (usually pronounced as /pɪk/) is a family of microcontrollers made by Microchip Technology, derived from the PIC1640 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to ''Peripher ...
's oscillator start-up timer holds the device's reset for a 1024-oscillator-cycle delay to allow the oscillator to stabilize.
Microchip - reset
retrieved 27 October 2011
See also
*Power-on reset
A power-on reset (PoR, POR) generator is a microcontroller or microprocessor peripheral that generates a reset signal when power is applied to the device. It ensures that the device starts operating in a known state.
PoR generator
In VLSI d ...
* Brown-out reset
*Watchdog timer
A watchdog timer (WDT, or simply a ''watchdog''), sometimes called a ''computer operating properly timer'' (''COP timer''), is an electronic or software timer that is used to detect and recover from computer malfunctions. Watchdog timers are wide ...
*Low-voltage detect
A low-voltage detect (LVD) is a microcontroller or microprocessor peripheral that generates a reset signal when the Vcc supply voltage falls below Vref. Sometimes is combined with power-on reset (POR) and then it is called POR-LVD.
See also
*Pow ...
References
Embedded systems
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