ATMEGA8HVA-4TU Atmel, ATMEGA8HVA-4TU Datasheet - Page 25

• Manufacturer Part Number: ATMEGA8HVA-4TU
• Description: MCU AVR 8K FLASH 4MHZ 28-TSOP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8HVA-4TU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 7
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 9 V
• Data Converters: A/D 5x12b
• Oscillator Type: External
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 28-TSOP
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.1.5
9.1.6
9.2
9.3
8024A–AVR–04/08
Clock Sources
Calibrated Fast RC Oscillator
Coulomb Counter ADC Clock - clk
Watchdog Timer and Battery Protection Clock
The Coulomb Counter ADC is provided with a dedicated clock domain. This allows operating the
Coulomb Counter ADC in low power modes like Power-save for continuous current
measurements.
The Watchdog Timer and Battery Protection are provided with a dedicated clock domain. This
allows operation in all modes except Power-off. It also allows very low power operation by utiliz-
ing an Ultra Low Power RC Oscillator dedicated to this purpose.
The following section describe the clock sources available in the device. The clocks are input to
the AVR clock generator, and routed to the appropriate modules.
The calibrated Fast RC Oscillator by default provides a 8.0 MHz clock to the system clock pres-
caler. The frequency is nominal value at 70°C. This clock will operate with no external
components. With an accurate time reference and by using runtime calibration, this oscillator
can be calibrated to an accuracy of +/- 1. % over the entire temperature range. During reset,
hardware loads the calibration byte into the FOSCCAL Register and thereby automatically cali-
brates the Fast RC Oscillator. At 70°C, this calibration gives a frequency of 8 MHz ± 4%. The
oscillator can be calibrated to any frequency in the range 7.3- 8.1 MHz by changing the FOSC-
CAL register. For more information on the pre-programmed calibration value, see the section
”Reading the Signature Row from Software” on page
clock is given by the
Start-up time of the chip is referred to as a number of Prescaled Fast RC Oscillator cycles (CK)
and a number of ULP oscillator cycles. The start-up time is selected by SUT fuses as defined in
Table 9-1 on page
Table 9-1.
Notes:
SUT3..0
111
000
001
010
011
100
101
110
1. The device is shipped with this option selected.
2. The actual value of the added, selectable 4- 512 ms delay depends on the actual frequency of
(1)
the
on page 165
“Ultra Low Power RC
Start-up times according to SUT fuse selection.
25.
CCADC
”System Clock Prescaler” on page
Start-up Time from
Power-save
6 CK
6 CK
6 CK
6 CK
6 CK
6 CK
6 CK
6 CK
Oscillator”. See
Additional Delay from Reset, Typical Values
Table 9-2 on page 27
144. Note that the frequency of the system
ATmega8HVA/16HVA
27.
14 CK + 128 ms
14 CK + 256 ms
14 CK + 512 ms
14 CK + 16 ms
14 CK + 32 ms
14 CK + 64 ms
14 CK + 4 ms
14 CK + 8 ms
and
”Electrical Characteristics”
(2)
25