ATTINY20-EK1 Atmel, ATTINY20-EK1 Datasheet - Page 23

• 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

6.5.3
8235B–AVR–04/11
OSCCAL – Oscillator Calibration Register
requirements. As the prescaler divides the master clock input to the MCU, the speed of all syn-
chronous peripherals is reduced accordingly. The division factors are given in
Table 6-4.
To avoid unintentional changes of clock frequency, a protected change sequence must be fol-
lowed to change the CLKPS bits:
At start-up, the CLKPS bits will be reset to 0b0011 to select the clock division factor of 8. The
application software must ensure that a sufficient division factor is chosen if the selected clock
source has a higher frequency than the maximum frequency of the device at the present operat-
ing conditions.
.
• Bits 7:0
The oscillator calibration register is used to trim the calibrated internal oscillator and remove pro-
cess variations from the oscillator frequency. A pre-programmed calibration value is
automatically written to this register during chip reset, giving the factory calibrated frequency as
specified in
Bit
0x39
Read/Write
Initial Value
1. Write the signature for change enable of protected I/O register to register CCP
2. Within four instruction cycles, write the desired value to CLKPS bits
CLKPS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
–
Table 20-2, “Calibration Accuracy of Internal RC Oscillator,” on page
CAL[7:0]: Oscillator Calibration Value
CAL7
Clock Prescaler Select
R/W
7
0
CLKPS2
CAL6
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
R/W
6
0
CAL5
R/W
5
0
CLKPS1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
CAL4
R/W
4
0
CAL3
R/W
3
0
CLKPS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
CAL2
R/W
2
0
CAL1
R/W
1
0
Clock Division Factor
CAL0
R/W
0
0
8 (default)
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
128
256
16
32
64
Table
1
2
4
ATtiny20
OSCCAL
174.
6-4.
23