ATtiny13A datasheet(103/174 Pages) ATMEL

103 / 174 page

103

8126D–AVR–11/09

ATtiny13A

17. Memory Programming

This section describes how ATtiny13A memories can be programmed.

17.1 Program And Data Memory Lock Bits

ATtiny13A provides two lock bits which can be left unprogrammed (“1”) or can be programmed

(“0”) to obtain the additional security listed in Table 17-2 on page 103. The lock bits can be

erased to “1” with the Chip Erase command, only.

Program memory can be read out via the debugWIRE interface when the DWEN fuse is pro-

grammed, even if the lock bits are set. Thus, when lock bit security is required, debugWIRE

should always be disabled by clearing the DWEN fuse.

Note:

1. “1” means unprogrammed, “0” means programmed

Notes: 1. Program fuse bits before lock bits. See section “Fuse Bytes” on page 104.

2. “1” means unprogrammed, “0” means programmed

Table 17-1.

Lock Bit Byte

Bit No

Description

Default Value (1)

–

1 (unprogrammed)

–

1 (unprogrammed)

–

1 (unprogrammed)

–

1 (unprogrammed)

–

1 (unprogrammed)

–

1 (unprogrammed)

LB2

Lock bit

1 (unprogrammed)

LB1

Lock bit

1 (unprogrammed)

Table 17-2.

Lock Bit Protection Modes

Memory Lock Bits (1) (2)

Protection Type

LB Mode

LB2

LB1

No memory lock features enabled.

Further programming of the Flash and EEPROM is disabled in

High-voltage and Serial Programming mode. Fuse bits are

locked in both Serial and High-voltage Programming mode.

debugWire is disabled.

Further programming and verification of the Flash and

EEPROM is disabled in High-voltage and Serial Programming

mode. Fuse bits are locked in both Serial and High-voltage

Programming mode. debugWire is disabled.

ATtiny13A Datasheet(PDF) 103 Page - ATMEL Corporation

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