ATMEGA8HVD-4MX Atmel, ATMEGA8HVD-4MX Datasheet - Page 24

• Manufacturer Part Number: ATMEGA8HVD-4MX
• Description: MCU AVR 8K FLASH 2.1-8V 4MHZ QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8HVD-4MX

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 5
• 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): 2 V ~ 2.4 V
• Data Converters: A/D 1x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 18-MLF® Exposed Pad (Staggered Leads), DFN
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Connectivity: -

8.4
8.5
8.6
8.7
8.8
24
Slow RC Oscillator
Ultra Low Power RC Oscillator
CPU, I/O, Flash, and ADC Clock
Watchdog Timer and Battery Protection
Clock Startup Sequence
ATmega4HVD/8HVD
The Slow RC Oscillator provides a 131 kHz clock (typical value, refer to section "Electrical
Characteristics" on page 164 for details). This clock can be used as a timing reference for run-
time calibration of the Fast RC Oscillator and for accurately determining the actual ULP Oscil-
lator frequency, refer to
To provide good accuracy when used as a timing reference, the Slow RC Oscillator has cali-
bration bytes stored in the signature address space, refer to section
Row from Software” on page 124
in μs as a function of temperature is given by:
where T is the die temperature in Kelvin and T
signature row. The die temperature can be found using the ADC, refer to
Digital Converter” on page 90
The Ultra Low Power RC Oscillator (ULP Oscillator) provides a 128 kHz clock (typical value,
refer to section
for determining the actual clock period of the ULP Oscillator:
1. To determine the actual clock period as a function of die temperature, the Oscillator
2. To determine a fixed value for the actual clock period independent of the die tempera-
The clock source for the CPU, I/O, Flash, and ADC is the calibrated Fast RC Oscillator.
The clock source for the Watchdog Timer and Battery Protection is the Ultra Low Power RC
Oscillator. The Oscillator is automatically enabled in all operational modes. It is also enabled
during reset.
When the CPU wakes up from Power-save, the CPU clock source is used to time the start-up,
ensuring a stable clock before instruction execution starts. When the CPU starts from reset,
there is an additional delay allowing the voltage regulator to reach a stable level before com-
mencing normal operation. The Ultra Low Power RC Oscillator is used for timing this real-time
part of the start-up time. Start-up times are determined by the SUT Fuses as shown in
Sampling Interface should be used. Refer to section
face” on page 27
ture, for example to determine the best setting of the Battery Protection timing, use the
calibration byte ULP_RC_FRQ stored in the signature address space, refer to section
”Reading the Signature Row from Software” on page 124
Clock period
”Electrical Characteristics” on page
for details.
”OSI – Oscillator Sampling Interface” on page 27
=
Slow RC Word
-------------------------------------- - (1-Slow RC Temp Prediction T T
for details.
1024
for details. The actual clock period of the Slow RC Oscillator
⋅
HOT
is the calibration temperature stored in the
142). There are two alternative methods
”OSI – Oscillator Sampling Inter-
for details.
(
”Reading the Signature
–
for details.
HOT
”ADC - Analog-to-
) )
8052B–AVR–09/08
Table