ATTINY28V-1AC Atmel, ATTINY28V-1AC Datasheet - Page 7

• Manufacturer Part Number: ATTINY28V-1AC
• Description: IC AVR MCU 2K 1.2MHZ 1.8V 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY28V-1AC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 1.2MHz
• Peripherals: POR, WDT
• Number Of I /o: 11
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Ram Size: -
• Data Converters: -
• Connectivity: -

System Clock and
Clock Options
Internal RC Oscillator
Calibrated Internal RC
Oscillator
Crystal Oscillator
External Clock
1062F–AVR–07/06
The device has the following clock source options, selectable by Flash Fuse bits as
shown in Table 1.
Table 1. Device Clocking Option Select
Note:
The various choices for each clocking option give different start-up times as shown in
Table 5 on page 16.
The internal RC oscillator option is an on-chip calibrated oscillator running at a nominal
frequency of 1.2 MHz. If selected, the device can operate with no external components.
The device is shipped with this option selected.
The calibrated internal oscillator provides a fixed 1.2 MHz (nominal) clock at 3V and
25°C. This clock may be used as the system clock. This oscillator can be calibrated by
writing the calibration byte to the OSCCAL register. When this oscillator is used as the
chip clock, the Watchdog oscillator will still be used for the Watchdog Timer and for the
reset time-out. For details on how to use the pre-programmed calibration value, see the
section “Calibration Byte” on page 46.
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier, which
can be configured for use as an on-chip oscillator, as shown in Figure 5. Either a quartz
crystal or a ceramic resonator may be used. When the INTCAP fuse is programmed,
internal load capacitors with typical values 50 pF are connected between XTAL1/XTAL2
and ground.
Figure 5. Oscillator Connections
Note:
To drive the device from an external clock source, XTAL2 should be left unconnected
while XTAL1 is driven as shown in Figure 6.
Clock Option
External Crystal/Ceramic Resonator
External Low-frequency Crystal
External RC Oscillator
Internal RC Oscillator
External Clock
“1” means unprogrammed, “0” means programmed.
1. When using the MCU oscillator as a clock for an external device, an HC buffer should
be connected as indicated in the figure.
HC
MAX 1 HC BUFFER
C2
C1
XTAL2
XTAL1
GND
ATtiny28L/V
1111 - 1010
1001 - 1000
0111 - 0101
0100 - 0010
0001 - 0000
CKSEL3..0
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