AT90PWM2 datasheet(295/365 Pages) ATMEL

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295

AT90PWM2/3

4317B–AVR–02/05

Parallel Programming

Enter Programming Mode

The following algorithm puts the device in Parallel (High-voltage) > Programming mode:

Set Prog_enable pins listed in Table 124. to “0000”, RESET pin to “0” and Vcc to

0V.

Apply 4.5 - 5.5V between VCC and GND. Ensure that Vcc reaches at least 1.8V

within the next 20µs.

Wait 20 - 60µs, and apply 11.5 - 12.5V to RESET.

Keep the Prog_enable pins unchanged for at least 10µs after the High-voltage

has been applied to ensure the Prog_enable Signature has been latched.

Wait at least 300µs before giving any parallel programming commands.

Exit Programming mode by power the device down or by bringing RESET pin to

0V.

If the rise time of the Vcc is unable to fulfill the requirements listed above, the following

alternative algorithm can be used.

Set Prog_enable pins listed in Table 124. to “0000”, RESET pin to “0” and Vcc to

0V.

Apply 4.5 - 5.5V between VCC and GND.

Monitor Vcc, and as soon as Vcc reaches 0.9 - 1.1V, apply 11.5 - 12.5V to

RESET.

Keep the Prog_enable pins unchanged for at least 10µs after the High-voltage

has been applied to ensure the Prog_enable Signature has been latched.

Wait until Vcc actually reaches 4.5 -5.5V before giving any parallel programming

commands.

Exit Programming mode by power the device down or by bringing RESET pin to

0V.

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.

Chip Erase

The Chip Erase will erase the Flash and EEPROM

(1) memories plus Lock bits. The Lock

bits are not reset until the program memory has been completely erased. The Fuse bits

are not changed. A Chip Erase must be performed before the Flash and/or EEPROM

are reprogrammed.

Note:

1. The EEPRPOM memory is preserved during Chip Erase if the EESAVE Fuse is

programmed.

Load Command “Chip Erase”

Set XA1, XA0 to “10”. This enables command loading.

Set BS1 to “0”.

Set DATA to “1000 0000”. This is the command for Chip Erase.

Give XTAL1 a positive pulse. This loads the command.

AT90PWM2 Datasheet(PDF) 295 Page - ATMEL Corporation

AT90PWM2 Datasheet(HTML) 295 Page - ATMEL Corporation

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