ATTINY20-XU Atmel, ATTINY20-XU Datasheet - Page 36

• Manufacturer Part Number: ATTINY20-XU
• Description: MCU AVR 2KB FLASH 12MHZ 14TSSOP
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY20-XU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 12
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Processor Series: ATtiny
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: SPI, TWI
• Maximum Clock Frequency: 12 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 2
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

36
ATtiny20
Watchdog System Reset mode. If the interrupt is not executed before the next time-out, a Sys-
tem Reset will be applied.
Table 8-2.
Note:
• Bit 4 – Res: Reserved Bit
This bit is reserved and will always read as zero.
• Bit 3 – WDE: Watchdog System Reset Enable
WDE is overridden by WDRF in RSTFLR. This means that WDE is always set when WDRF is
set. To clear WDE, WDRF must be cleared first. This feature ensures multiple resets during con-
ditions causing failure, and a safe start-up after the failure.
• Bits 5, 2:0 – WDP[3:0]: Watchdog Timer Prescaler 3 - 0
The WDP[3:0] bits determine the Watchdog Timer prescaling when the Watchdog Timer is run-
ning. The different prescaling values and their corresponding time-out periods are shown in
Table 8-3 on page
Table 8-3.
WDTON
WDP3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
1. WDTON configuration bit set to “0“ means programmed and “1“ means unprogrammed.
(1)
WDP2
0
0
0
0
1
1
1
1
0
0
WDE
Watchdog Timer Configuration
Watchdog Timer Prescale Select
0
0
1
1
x
36.
WDP1
WDIE
0
0
1
1
0
0
1
1
0
0
0
1
0
1
x
WDP0
Mode
Stopped
Interrupt
System Reset
Interrupt and System Reset
System Reset
0
1
0
1
0
1
0
1
0
1
1024K (1048576) cycles
WDT Oscillator Cycles
128K (131072) cycles
256K (262144) cycles
512K (524288) cycles
16K (16384) cycles
32K (32768) cycles
64K (65536) cycles
2K (2048) cycles
4K (4096) cycles
8K (8192) cycles
Number of
Action on Time-out
None
Interrupt
Reset
Interrupt, then go to System Reset Mode
Reset
Typical Time-out
at V
0.125 s
16 ms
32 ms
64 ms
0.25 s
CC
0.5 s
1.0 s
2.0 s
4.0 s
8.0 s
8235B–AVR–04/11
= 5.0V