ATAVRSB202 Atmel, ATAVRSB202 Datasheet - Page 79

• Manufacturer Part Number: ATAVRSB202
• Description: KIT BATT MGMT FOR ATMEGA32HVB
• Manufacturer: Atmel

Specifications of ATAVRSB202

• Main Purpose: *
• Embedded: *
• Utilized Ic / Part: *
• Primary Attributes: *
• Secondary Attributes: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

16. Timer/Counter0 and Timer/Counter1 Prescalers
16.1
16.1.1
16.1.2
8042B–AVR–06/10
Overview
Internal Clock Source
Prescaler Reset
Timer/Counter1 and Timer/Counter0 share the same prescaler module, but the Timer/Counters
can have different prescaler settings. The description below applies to both Timer/Counter1 and
Timer/Counter0.
The Timer/Counter can be clocked directly by the system clock (by setting the CSn2:0 = 1). This
provides the fastest operation, with a maximum Timer/Counter clock frequency equal to system
clock frequency (f
clock source. The prescaled clock has a frequency of either f
f
The prescaler is free running, i.e., operates independently of the Clock Select logic of the
Timer/Counter, and it is shared by Timer/Counter1 and Timer/Counter0. Since the prescaler is
not affected by the Timer/Counter’s clock select, the state of the prescaler will have implications
for situations where a prescaled clock is used. One example of prescaling artifacts occurs when
the timer is enabled and clocked by the prescaler (6 > CSn2:0 > 1). The number of system clock
cycles from when the timer is enabled to the first count occurs can be from 1 to N+1 system
clock cycles, where N equals the prescaler divisor (8, 64, 256, or 1024).
It is possible to use the prescaler reset for synchronizing the Timer/Counter to program execu-
tion. However, care must be taken if the other Timer/Counter that shares the same prescaler
also uses prescaling. A prescaler reset will affect the prescaler period for all Timer/Counters it is
connected to.
Figure 16-1. Prescaler for Timer/Counter
CLK_I/O
/1024.
PSRSYNC
Tn
clk
I/O
CLK_I/O
Synchronization
). Alternatively, one of four taps from the prescaler can be used as a
Clear
CSn0
CSn1
CSn2
ATmega16HVB/32HVB
CLK_I/O
clk
n
Tn
/8, f
CLK_I/O
/64, f
CLK_I/O
/256, or
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