ATmega8HVA Atmel Corporation, ATmega8HVA Datasheet - Page 31

• Manufacturer Part Number: ATmega8HVA
• Manufacturer: Atmel Corporation

Specifications of ATmega8HVA

• Flash (kbytes): 8 Kbytes
• Pin Count: 28
• Max. Operating Frequency: 4 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 3
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 6
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 6
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 256
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -20 to 85
• I/o Supply Class: 1.8 to 9.0
• Operating Voltage (vcc): 1.8 to 9.0
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

9.13.2
9.13.3
8024A–AVR–04/08
MCUCR – MCU Control Register
CLKPR – Clock Prescale Register
The FCAL[4:0] bits are used to tune the frequency within the selected range. A setting of 0x00
gives the lowest frequency in that range, and a setting of 0x1F gives the highest frequency in the
range. Incrementing FCAL[4:0] by 1 will give a frequency increment of less than 1.5 % in the fre-
quency range 7.3-8.1 MHz. With an accurate time reference, an oscillator accuracy of ±1% can
be achieved after calibration. The frequency will drift with temperature, so run-time calibration
will be required to maintain the accuracy. Refer to
28
The default FOSCCAL value found in the signature row, is selected such that it is in the the
lower half of a segment (see
oscillator). It is therefore sufficient to use the default segment and the one below to calibrate the
frequency over the whole temperature range. To avoid a large frequency change when shifting
between the two segments, a FOSC SEGMENT value is stored in the signature row. This is the
first FOSCCAL value giving a lower frequency than the lowest value in the default segment, and
should be used when calibrating the Fast RC oscillator.
• Bit 5 – CKOE: Clock Output
When this bit is written to one, the CPU clock divided by 2 is output on the PB0 pin.
Bit
0x35 (0x55)
Read/Write
Initial Value
Bit
(0x61)
Read/Write
Initial Value
for details.
CLKPCE
-–
R
7
0
R/W
7
0
R
6
–
0
R
6
–
0
Figure 30-1 on page 174
CKOE
R/W
5
0
R
5
–
0
PUD
R/W
4
0
R
4
–
0
”OSI – Oscillator Sampling Interface” on page
R
3
–
0
R
3
–
0
for typical characteristics of the FAST RC
ATmega8HVA/16HVA
R
2
–
0
R
2
–
0
R
1
–
0
CLKPS1
R/W
1
1
R
0
–
0
CLKPS0
R/W
MCUCR
0
1
CLKPR
31