Rainbow-electronics ATtiny861_V Manual de usuario descargar pdf (Pagina 173)

173

2588B–AVR–11/06

ATtiny261/461/861

22.7 Parallel Programming

22.7.1 Enter Programming Mode

The following algorithm puts the device in parallel programming mode:

1. Apply 4.5 - 5.5V between V

and GND.

2. Set RESET

to “0” and toggle XTAL1 at least six times.

3. Set the Prog_enable pins listed in Table 22-10 on page 172 to “0000” and wait at least

100 ns.

4. Apply 11.5 - 12.5V to RESET

. Any activity on Prog_enable pins within 100 ns after +12V

has been applied to RESET

, will cause the device to fail entering programming mode.

5. Wait at least 50 µs before sending a new command.

22.7.2 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.

Table 22-11. XA1 and XA0 Coding

XA1 XA0 Action when XTAL1 is Pulsed

0 0 Load Flash or EEPROM Address (High or low address byte determined by BS1).

0 1 Load Data (High or Low data byte for Flash determined by BS1).

1 0 Load Command

1 1 No Action, Idle

Table 22-12. Command Byte Bit Coding

Command Byte Command Executed

1000 0000 Chip Erase

0100 0000 Write Fuse bits

0010 0000 Write Lock bits

0001 0000 Write Flash

0001 0001 Write EEPROM

0000 1000 Read Signature Bytes and Calibration byte

0000 0100 Read Fuse and Lock bits

0000 0010 Read Flash

0000 0011 Read EEPROM

1 2 ... 168 169 170 171 172 173 174 175 176 177 178 ... 235 236

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