ATTINY261-20MUR Atmel, ATTINY261-20MUR Datasheet - Page 172

• Manufacturer Part Number: ATTINY261-20MUR
• Description: IC MCU AVR 2K FLASH 20MHZ 32QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY261-20MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.2.1
18.3
172
Signature Bytes
ATtiny261/461/861
Latching of Fuses
Table 18-5.
Notes:
Note that fuse bits are locked if Lock Bit 1 (LB1) is programmed. Fuse bits should be pro-
grammed before lock bits. The status of fuse bits is not affected by chip erase.
Fuse bits can also be read by device firmware. See section
Software” on page
Fuse values are latched when the device enters programming mode and changes to fuse values
have no effect until the part leaves programming mode. This does not apply to the EESAVE
Fuse which will take effect once it is programmed. Fuses are also latched on power-up.
All Atmel microcontrollers have a three-byte signature code which identifies the device. This
code can be read in both serial and High-voltage Programming mode, also when the device is
locked. The three bytes reside in a separate address space. The ATtiny261/461/861signature
bytes are given in
Table 18-6.
Fuse Low Byte
CKDIV8
CKOUT
SUT1
SUT0
CKSEL3
CKSEL2
CKSEL1
CKSEL0
Parts
ATtiny261
ATtiny461
ATtiny861
1. See
2. Allows system clock to be output on pin. See
3. The default value results in maximum start-up time for the default clock source. See
4. The default setting results in internal RC Oscillator @ 8.0 MHz. See
(2)
(1)
on page 28
details.
Fuse Low Byte
Device ID
“System Clock Prescaler” on page 31
Table
167.
Bit No
for details.
7
6
5
4
3
2
1
0
18-6.
Description
Divide clock by 8
Clock Output Enable
Select start-up time
Select start-up time
Select Clock source
Select Clock source
Select Clock source
Select Clock source
0x000
0x1E
0x1E
0x1E
Signature Bytes Address
for details.
“Clock Output Buffer” on page 32
0x001
0x91
0x92
0x93
“Reading Fuse and Lock Bits from
1 (unprogrammed)
Default Value
0 (programmed)
1 (unprogrammed)
0 (programmed)
0 (programmed)
0 (programmed)
1 (unprogrammed)
0 (programmed)
Table 6-6 on page 28
0x002
0x0C
0x0D
0x08
2588E–AVR–08/10
(3)
(4)
(4)
(4)
for details.
(3)
(4)
Table 6-7
for