Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
37
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
From the time the CLKPS values are written, it takes between T1 + T2 and T1 + 2 * T2 before the new clock
frequency is active. In this interval, 2 active clock edges are produced. Here, T1 is the previous clock period,
and T2 is the period corresponding to the new prescaler setting.
frequency is active. In this interval, 2 active clock edges are produced. Here, T1 is the previous clock period,
and T2 is the period corresponding to the new prescaler setting.
To avoid unintentional changes of clock frequency, a special write procedure must be followed to change the
CLKPS bits:
CLKPS bits:
1. Write the Clock Prescaler Change Enable (CLKPCE) bit to one and all other bits in CLKPR to zero.
2.
Within four cycles, write the desired value to CLKPS while writing a zero to CLKPCE.
Interrupts must be disabled when changing prescaler setting to make sure the write procedure is not interrupted.