ATTINY461-20PU Atmel, ATTINY461-20PU Datasheet - Page 170

• Manufacturer Part Number: ATTINY461-20PU
• Description: Microcontrollers (MCU) 4kB Flash 0.256kB EEPROM 16 I/O Pins
• Manufacturer: Atmel

Specifications of ATTINY461-20PU

• Processor Series: ATTINY4x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: 2-Wire/SPI/USI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 2
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 11-ch x 10-bit
• Program Memory Type: Flash
• Program Memory Size: 4 KB
• Package / Case: PDIP-20
• Package: 20PDIP
• Device Core: AVR
• Family Name: ATtiny
• Maximum Speed: 20 MHz
• Ram Size: 256 Byte
• Operating Temperature: -40 to 85 °C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18. Memory Programming
18.1
170
Program And Data Memory Lock Bits
ATtiny261/461/861
This section describes the different methods for programming ATtiny261/461/861 memories.
The ATtiny261/461/861 provides two lock bits which can be left unprogrammed (“1”) or can be
programmed (“0”) to obtain the additional security listed in
erased to “1” with the Chip Erase command.
The device has no separate boot loader section. The SPM instruction is enabled for the whole
Flash, if the SELFPROGEN fuse is programmed (“0”), otherwise it is disabled.
Program memory can be read out via the debugWIRE interface when the DWEN fuse is pro-
grammed, even if lock bits are set. Thus, when lock bit security is required, debugWIRE should
always be disabled by clearing the DWEN fuse.
Table 18-1.
Note:
Table 18-2.
Notes:
Lock bits can also be read by device firmware. See section
Software” on page
LB2
LB1
LB Mode
Lock Bit Byte
Memory Lock Bits
1
2
3
“1” means unprogrammed, “0” means programmed.
1. Program fuse bits before programming LB1 and LB2.
2. “1” means unprogrammed, “0” means programmed.
Lock Bit Byte
Lock Bit Protection Modes.
LB2
167.
1
1
0
(1) (2)
LB1
1
0
0
Bit No
7
6
5
4
3
2
1
0
Protection Type
No memory lock features enabled.
Further programming of the Flash and EEPROM is disabled in
High-voltage and Serial Programming mode. The Fuse bits are
locked in both Serial and High-voltage Programming mode.
Further programming and verification of the Flash and EEPROM
is disabled in High-voltage and Serial Programming mode. The
Fuse bits are locked in both Serial and High-voltage
Programming mode.
Description
–
–
–
–
–
–
Lock bit
Lock bit
(1)
Table
“Reading Fuse and Lock Bits from
18-2. The lock bits can only be
Default Value
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
2588E–AVR–08/10
(1)