ATTINY13-20SSU Atmel, ATTINY13-20SSU Datasheet - Page 41

• Manufacturer Part Number: ATTINY13-20SSU
• Description: IC MCU AVR 1K FLASH 20MHZ 8SOIC
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY13-20SSU

• 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-SOIC (3.9mm Width)
• For Use With: ATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Connectivity: -

8.4
8.4.1
8.4.2
2535J–AVR–08/10
Register Description
MCUSR – MCU Status Register
WDTCR – Watchdog Timer Control Register
The MCU Status Register provides information on which reset source caused an MCU Reset.
• Bits 7:4 – Res: Reserved Bits
These bits are reserved bits in the ATtiny13 and will always read as zero.
• Bit 3 – WDRF: Watchdog Reset Flag
This bit is set if a Watchdog Reset occurs. The bit is reset by a Power-on Reset, or by writing a
logic zero to the flag.
• Bit 2 – BORF: Brown-out Reset Flag
This bit is set if a Brown-out Reset occurs. The bit is reset by a Power-on Reset, or by writing a
logic zero to the flag.
• Bit 1 – EXTRF: External Reset Flag
This bit is set if an External Reset occurs. The bit is reset by a Power-on Reset, or by writing a
logic zero to the flag.
• Bit 0 – PORF: Power-on Reset Flag
This bit is set if a Power-on Reset occurs. The bit is reset only by writing a logic zero to the flag.
To make use of the Reset Flags to identify a reset condition, the user should read and then reset
the MCUSR as early as possible in the program. If the register is cleared before another reset
occurs, the source of the reset can be found by examining the Reset Flags.
• Bit 7 - WDTIF: Watchdog Timer Interrupt Flag
This bit is set when a time-out occurs in the Watchdog Timer and the Watchdog Timer is config-
ured for interrupt. WDTIF is cleared by hardware when executing the corresponding interrupt
handling vector. Alternatively, WDTIF is cleared by writing a logic one to the flag. When the I-bit
in SREG and WDTIE are set, the Watchdog Time-out Interrupt is executed.
• Bit 6 - WDTIE: Watchdog Timer Interrupt Enable
When this bit is written to one and the I-bit in the Status Register is set, the Watchdog Interrupt is
enabled. If WDE is cleared in combination with this setting, the Watchdog Timer is in Interrupt
Mode, and the corresponding interrupt is executed if time-out in the Watchdog Timer occurs.
If WDE is set, the Watchdog Timer is in Interrupt and System Reset Mode. The first time-out in
the Watchdog Timer will set WDTIF. Executing the corresponding interrupt vector will clear
WDTIE and WDTIF automatically by hardware (the Watchdog goes to System Reset Mode).
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
WDTIF
R/W
7
0
R
7
–
0
WDTIE
R/W
6
0
R
6
–
0
WDP3
R/W
5
0
R
5
–
0
WDCE
R/W
4
0
R
4
–
0
WDE
R/W
WDRF
R/W
3
X
3
WDP2
R/W
See Bit Description
BORF
2
0
R/W
2
WDP1
R/W
EXTRF
1
0
R/W
1
WDP0
R/W
PORF
0
0
R/W
0
WDTCR
MCUSR
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