ATTINY13-20PJ Atmel, ATTINY13-20PJ Datasheet - Page 38

• Manufacturer Part Number: ATTINY13-20PJ
• Description: IC MCU AVR 1K 5V 20MHZ 8DIP
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY13-20PJ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 6
• Program Memory Size: 1KB (512 x 16)
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 64 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Connectivity: -
• Other names: ATTINY13-24PJ; ATTINY13-24PJ

38
ATtiny13
value is reached. If the system doesn't restart the counter, an interrupt or system reset will be
issued.
Figure 8-7.
In Interrupt mode, the WDT gives an interrupt when the timer expires. This interrupt can be used
to wake the device from sleep-modes, and also as a general system timer. One example is to
limit the maximum time allowed for certain operations, giving an interrupt when the operation
has run longer than expected. In System Reset mode, the WDT gives a reset when the timer
expires. This is typically used to prevent system hang-up in case of runaway code. The third
mode, Interrupt and System Reset mode, combines the other two modes by first giving an inter-
rupt and then switch to System Reset mode. This mode will for instance allow a safe shutdown
by saving critical parameters before a system reset.
The Watchdog always on (WDTON) fuse, if programmed, will force the Watchdog Timer to Sys-
tem Reset mode. With the fuse programmed the System Reset mode bit (WDE) and Interrupt
mode bit (WDTIE) are locked to 1 and 0 respectively. To further ensure program security, altera-
tions to the Watchdog set-up must follow timed sequences. The sequence for clearing WDE and
changing time-out configuration is as follows:
1. In the same operation, write a logic one to the Watchdog change enable bit (WDCE)
2. Within the next four clock cycles, write the WDE and Watchdog prescaler bits (WDP) as
and WDE. A logic one must be written to WDE regardless of the previous value of the
WDE bit.
desired, but with the WDCE bit cleared. This must be done in one operation.
WATCHDOG
RESET
OSCILLATOR
Watchdog Timer
128kHz
WDTIE
WDTIF
WDE
WDP0
WDP1
WDP2
WDP3
MCU RESET
INTERRUPT
2535J–AVR–08/10