ATTINY28V-1AC Atmel, ATTINY28V-1AC Datasheet - Page 16

• 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: -

Power-on Reset
16
ATtiny28L/V
Table 5. ATtiny28 Clock Options and Start-up Time
Note:
This table shows the start-up times from reset. From Power-down mode, only the clock
counting part of the start-up time is used. The Watchdog oscillator is used for timing the
real-time part of the start-up time. The number WDT oscillator cycles used for each
time-out is shown in Table 6.
Table 6. Number of Watchdog Oscillator Cycles
The frequency of the Watchdog oscillator is voltage-dependent, as shown in the section
“Typical Characteristics” on page 57.
The device is shipped with CKSEL = 0010.
A Power-on Reset (POR) pulse is generated by an on-chip detection circuit. The detec-
tion level is nominally 1.4V. The POR is activated whenever V
level. The POR circuit can be used to trigger the start-up reset, as well as detect a fail-
ure in supply voltage.
The Power-on Reset (POR) circuit ensures that the device is reset from power-on.
Reaching the Power-on Reset threshold voltage invokes a delay counter, which deter-
mines the delay for which the device is kept in RESET after V
period of the delay counter can be defined by the user through the CKSEL fuses. The
different selections for the delay period are presented in Table 5. The RESET signal is
Time-out
4.2 ms
67 ms
CKSEL3..0
1111
1110
1101
1100
1011
1010
1001
1000
0111
0110
0101
0100
0011
0010
0001
0000
1. Due to limited number of clock cycles in the start-up period, it is recommended that
ceramic resonator be used.
Clock Source
External Crystal/Ceramic Resonator
External Crystal/Ceramic Resonator
External Crystal/Ceramic Resonator
External Crystal/Ceramic Resonator
External Crystal/Ceramic Resonator
External Crystal/Ceramic Resonator
External Low-frequency Crystal
External Low-frequency Crystal
External RC Oscillator
External RC Oscillator
External RC Oscillator
Internal RC Oscillator
Internal RC Oscillator
Internal RC Oscillator
External Clock
External Clock
Number of Cycles
1K
16K
(1)
(1)
(1)
1K CK
4.2 ms + 1K CK
67 ms + 1K CK
16K CK
4.2 ms + 16K CK
67 ms + 16K CK
67 ms + 1K CK
67 ms + 32K CK
6 CK
4.2 ms + 6 CK
67 ms + 6 CK
6 CK
4.2 ms + 6 CK
67 ms + 6 CK
6 CK
4.2 ms + 6 CK
Start-up Time at 2.7V
CC
is below the detection
CC
rise. The time-out
1062F–AVR–07/06