at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 255

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

22.7
22.7.1
22.7.2
22.7.3
7734M–AVR–03/10
Parallel Programming
Enter Programming Mode
Considerations for Efficient Programming
Chip Erase
The following algorithm puts the device in Parallel (High-voltage) > Programming mode:
If the rise time of the Vcc is unable to fulfill the requirements listed above, the following alternative algo-
rithm can be used.
The loaded command and address are retained in the device during programming. For efficient program-
ming, the following should be considered.
The Chip Erase will erase the Flash and EEPROM
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:
Load Command “Chip Erase”
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• 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
• Address high byte needs only be loaded before programming or reading a new 256 word window in
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is programmed) and Flash after a Chip Erase.
Flash or 256 byte EEPROM. This consideration also applies to Signature bytes reading.
Set Prog_enable pins listed in Table 22-8. 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.
Set Prog_enable pins listed in Table 22-8. 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.
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.
Wait until RDY/BSY goes high before loading a new command.
1. The EEPRPOM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
(1)
memories plus Lock bits. The Lock bits are not reset
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