ATTINY20-EK1 Atmel, ATTINY20-EK1 Datasheet - Page 106

• Manufacturer Part Number: ATTINY20-EK1
• Description: KIT EVAL TOUCH ATTINY20
• Manufacturer: Atmel

Specifications of ATTINY20-EK1

• Sensor Type: *
• Sensing Range: *
• Interface: *
• Sensitivity: *
• Voltage - Supply: *
• Embedded: *
• Utilized Ic / Part: *
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: TinyAVR
• Kit Contents: Board
• Svhc: No SVHC (15-Dec-2010)
• Mcu Supported Families: ATtiny20
• Tool / Board Applications: Microcontroller
• Rohs Compliant: Yes
• Tool Type: Development Kit
• Cpu Core: AVR 8
• Data Bus Width: 8 bit
• Processor To Be Evaluated: ATtiny20
• Interface Type: Touch
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

106
ATtiny20
Enabling and disabling of the clock input must be done when Tn has been stable for at least one
system clock cycle, otherwise it is a risk that a false Timer/Counter clock pulse is generated.
Each half period of the external clock applied must be longer than one system clock cycle to
ensure correct sampling. The external clock must be guaranteed to have less than half the sys-
tem clock frequency (f
sampling, the maximum frequency of an external clock it can detect is half the sampling fre-
quency (Nyquist sampling theorem). However, due to variation of the system clock frequency
and duty cycle caused by Oscillator source (crystal, resonator, and capacitors) tolerances, it is
recommended that maximum frequency of an external clock source is less than f
An external clock source can not be prescaled.
Figure 13-2. Prescaler for Timer/Counter0
Note:
clk
PSR
T0
I/O
1. The synchronization logic on the input pins (
Synchronization
ExtClk
< f
Clear
clk_I/O
/2) given a 50/50% duty cycle. Since the edge detector uses
T0)
is shown in
Figure 13-1 on page 105
clk
T0
clk_I/O
8235B–AVR–04/11
/2.5.
.