AT90PWM2 datasheet(287/365 Pages) ATMEL

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4317K–AVR–03/2013

AT90PWM2/3/2B/3B

25.8

Parallel Programming

25.8.1

Enter Programming Mode

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

Set Prog_enable pins listed in Table 25-8. 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 alterna-

tive algorithm can be used.

Set Prog_enable pins listed in Table 25-8. 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.

25.8.2

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.

25.8.3

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 perfor med 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.

Give WR a negative pulse. This starts the Chip Erase. RDY/BSY goes low.

AT90PWM2 Datasheet(PDF) 287 Page - ATMEL Corporation

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