ATA5771 Datasheet, PDF (221/284 Pages) ATMEL Corporation – Microcontroller with UHF ASK/FSK Transmitter

ATtiny24/44/84
4. Keep the Prog_enable pins unchanged for at least 10 µs after the High-voltage has
been applied to ensure the Prog_enable Signature has been latched.
5. Release the Prog_enable[2] pin to avoid drive contention on the Prog_enable[2]/SDO
pin.
6. Wait until V_CC actually reaches 4.5 - 5.5V before giving any serial instructions on
SDI/SII.
7. Exit Programming mode by power the device down or by bringing RESET pin to 0V.
Table 19-15. High-voltage Reset Characteristics
Supply Voltage
V_CC
4.5V
5.5V
RESET Pin High-voltage Threshold
V_HVRST
11.5V
11.5V
Minimum High-voltage Period for
Latching Prog_enable
t_HVRST
100 ns
100 ns
19.7.2
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.
19.7.3
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 performed before the Flash and/or EEPROM are re-
programmed.
1. Load command “Chip Erase” (see Table 19-16 on page 172).
2. Wait after Instr. 3 until SDO goes high for the “Chip Erase” cycle to finish.
3. Load Command “No Operation”.
Note: 1. The EEPROM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
19.7.4
Programming the Flash
The Flash is organized in pages, see “Page Size” on page 162. When programming the Flash,
the program data is latched into a page buffer. This allows one page of program data to be pro-
grammed simultaneously. The following procedure describes how to program the entire Flash
memory:
8006G–AVR–01/08
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