atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 371

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

29.6
29.6.1
29.6.2
29.6.3
7766A–AVR–03/08
Parallel Programming
Enter Programming Mode
Considerations for Efficient Programming
Chip Erase
Table 29-12. No. of Words in a Page and No. of Pages in the EEPROM
The following algorithm puts the device in parallel programming mode:
The loaded command and address are retained in the device during programming. For efficient
programming, the following should be considered.
The Chip Erase will erase the Flash and EEPROM
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:
Load Command “Chip Erase”
1. Apply 4.5 - 5.5V between V
2. Set RESET to “0” and toggle XTAL1 at least six times.
3. Set the Prog_enable pins listed in
4. Apply 11.5 - 12.5V to RESET. Any activity on Prog_enable pins within 100 ns after
5. Wait at least 50 µs before sending a new command.
• The command needs only be loaded once when writing or reading multiple memory
• Skip writing the data value 0xFF, that is the contents of the entire EEPROM (unless the
• Address high byte needs only be loaded before programming or reading a new 256 word
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS1 to “0”.
3. Set DATA to “1000 0000”. This is the command for Chip Erase.
4. Give XTAL1 a positive pulse. This loads the command.
5. Give WR a negative pulse. This starts the Chip Erase. RDY/BSY goes low.
6. Wait until RDY/BSY goes high before loading a new command.
locations.
EESAVE Fuse is programmed) and Flash after a Chip Erase.
window in Flash or 256 byte EEPROM. This consideration also applies to Signature bytes
reading.
100 ns.
+12V has been applied to RESET, will cause the device to fail entering programming
mode.
EEPROM Size
1. The EEPRPOM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
1K bytes
Page Size
8 bytes
CC
and GND.
PCWORD
Table 29-8 on page 370
EEA[2:0]
(1)
memories plus Lock bits. The Lock bits are
Pages
No. of
128
PCPAGE
to “0000” and wait at least
EEA[9:3]
ATmega32U4
EEAMSB
9
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