Datasheet

112
ATtiny13
2535E–AVR–10/04
High-voltage Serial
Programming Algorithm
To program and verify the ATtiny13 in the High-voltage Serial Programming mode, the
following sequence is recommended (See instruction formats in Table 55):
Enter High-voltage Serial
Programming Mode
The following algorithm puts the device in High-voltage Serial Programming mode:
1. Apply 4.5 - 5.5V between V
CC
and GND.
2. Set RESET
pin to “0” and toggle SCI at least six times.
3. Set the Prog_enable pins listed in Table 53 to “000” and wait at least 100 ns.
4. Apply V
HVRST
- 12.5V to RESET. Keep the Prog_enable pins unchanged for at
least t
HVRST
after the High-voltage has been applied to ensure the Prog_enable
signature has been latched.
5. Shortly after latching the Prog_enable signature, the device will actively output
data on the Prog_enable[2]/SDO pin, and the resulting drive contention may
increase the power consumption. To minimize this drive contention, release the
Prog_enable[2] pin after t
HVRST
has elapsed.
6. Wait at least 50 µs before giving any serial instructions on SDI/SII.
Note: If the RESET pin is disabled by programming the RSTDISBL Fuse, it may not be possible
to follow the proposed algorithm above.The same may apply when External Crystal or
External RC configuration is selected because it is not possible to apply qualified CLKI
pulses. In such cases, the following algorithm should be followed:
1. Set Prog_enable pins listed in Table 53 to “000”.
2. Apply 4.5 - 5.5V between V
CC
and GND simultanously as 11.5 - 12.5V is applied
to RESET
.
3. Wait 100 ns.
4. Re-program the fuses to ensure that External Clock is selected as clock source
(CKSEL1:0 = 0b00) and RESET
pin is activated (RSTDISBL unprogrammed). If
Lock bits are programmed, a Chip Erase command must be executed before
changing the fuses.
5. Exit Programming mode by power the device down or by bringing RESET
pin to
0b0.
6. Enter Programming mode with the original algorithm, as described above.
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 54. High-voltage Reset Characteristics
Supply Voltage RESET Pin High-voltage Threshold
Minimum High-voltage Period
for Latching Prog_enable
V
CC
V
HVRST
t
HVRST
4.5V 12V 100 ns
5.5V 12 100 ns