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Parallel programming, Enter programming mode, Considerations for efficient programming – Rainbow Electronics ATmega162V User Manual

Page 235: Table 105, Atmega162/v

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235

ATmega162/V

2513E–AVR–09/03

Parallel Programming

Enter Programming Mode

The following algorithm puts the device in Parallel Programming mode:

1.

Apply 4.5 - 5.5V between V

CC

and GND, and wait at least 100 µs.

2.

Set RESET to “0” and toggle XTAL1 at least six times.

3.

Set the Prog_enable pins listed in Table 103 on page 234 to “0000” and wait at
least 100 ns.

4.

Apply 11.5 - 12.5V to RESET. Any activity on Prog_enable pins within 100 ns
after +12V has been applied to RESET, will cause the device to fail entering Pro-
gramming mode.

Considerations for Efficient
Programming

The loaded command and address are retained in the device during programming. For
efficient programming, the following should be considered.

The command needs only be loaded once when writing or reading multiple memory
locations.

Skip writing the data value 0xFF, that is the contents of the entire EEPROM (unless
the EESAVE Fuse is programmed) and Flash after a Chip Erase.

Address high byte needs only be loaded before programming or reading a new 256-
word window in Flash or 256 byte EEPROM. This consideration also applies to
Signature bytes reading.

Table 105. Command Byte Bit Coding

Command Byte

Command Executed

1000 0000

Chip Erase

0100 0000

Write Fuse Bits

0010 0000

Write Lock Bits

0001 0000

Write Flash

0001 0001

Write EEPROM

0000 1000

Read Signature Bytes and Calibration byte

0000 0100

Read Fuse and Lock Bits

0000 0010

Read Flash

0000 0011

Read EEPROM

Table 106. No. of Words in a Page and no. of Pages in the Flash

Flash Size

Page Size

PCWORD

No. of Pages

PCPAGE

PCMSB

8K words (16K bytes)

64 words

PC[5:0]

128

PC[12:6]

12

Table 107. No. of Words in a Page and no. of Pages in the EEPROM

EEPROM Size

Page Size

PCWORD

No. of pages

PCPAGE

EEAMSB

512 bytes

4 bytes

EEA[1:0]

128

EEA[8:2]

8