For Timer/Counter2, the possible prescaled selections are: clkT2S/8, clkT2S/32, clkT2S/64,
clkT2S/128, clkT2S/256, and clkT2S/1024. Additionally, clkT2S as well as 0 (stop) may be
selected. Setting the PSR2 bit in SFIOR resets the prescaler. This allows the user to
operate with a predictable prescaler.
Special Function IO Register –
SFIOR
Bit
7
ADTS2
R/W
0
6
ADTS1
R/W
0
5
ADTS0
R/W
0
4
ADHSM
R/W
0
3
ACME
R/W
0
2
1
PSR2
R/W
0
0
PSR10
R/W
0
PUD
R/W
0
SFIOR
Read/Write
Initial Value
• Bit 1 – PSR2: Prescaler Reset Timer/Counter2
When this bit is written to one, the Timer/Counter2 prescaler will be reset. The bit will be
cleared by hardware after the operation is performed. Writing a zero to this bit will have
no effect. This bit will always be read as zero if Timer/Counter2 is clocked by the internal
CPU clock. If this bit is written when Timer/Counter2 is operating in asynchronous
mode, the bit will remain one until the prescaler has been reset.
128
ATmega16(L)
2466E–AVR–10/02
ATMEL [ ATMEL ]
