atmega323l ATMEL Corporation, atmega323l Datasheet - Page 188

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Signature Bytes
Calibration Byte
Parallel Programming
Signal Names
188
ATmega323(L)
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The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are
locked if Lock bit1 (LB1) is programmed. Program the Fuse bits before programming the
Lock bits.
All Atmel microcontrollers have a 3-byte signature code which identifies the device. This
code can be read in both serial and parallel mode. The three bytes reside in a separate
address space.
For the ATmega323 the signature bytes are:
1. $000: $1E (indicates manufactured by Atmel)
2. $001: $95 (indicates 32KB Flash memory)
3. $002: $01 (indicates ATmega323 device when $001 is $95)
The ATmega323 has a one byte calibration value for the internal RC Oscillator. This
byte resides in the High Byte of address $000 in the signature address space. To make
use of this byte, it should be read from this location and written into the normal Flash
Program memory by the external programmer. At start-up, the user software must read
this Flash location and write the value to the OSCCAL Register.
This section describes how to parallel program and verify Flash Program memory,
EEPROM Data memory + Program And Data memory Lock bits and Fuse bits in the
ATmega323. Pulses are assumed to be at least 500ns unless otherwise noted.
In this section, some pins of the ATmega323 are referenced by signal names describing
their functionality during parallel programming, see Figure 93 and Table 64. Pins not
described in the following table are referenced by pin names.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a posi-
tive pulse. The bit coding are shown in Table 65.
When pulsing WR or OE, the command loaded determines the action executed. The
Command is a byte where the different bits are assigned functions as shown in Table
66.
When the BODEN Fuse is programmed (“0”), the Brown-out Detector is enabled.
See “Reset and Interrupt Handling” on page 22. Default value is unprogrammed
(“1”).
CKSEL3..0 select the clock source and the start-up delay after reset, according to
Table 1 on page 6 and Table 6 on page 27. Default value is “0010” (Internal RC
Oscillator, slowly rising power).
1457G–AVR–09/03