
168
8006K–AVR–10/10
ATtiny24/44/84
19.7
High-Voltage Serial Programming Algorithm
To program and verify the ATtiny24/44/84 in the High-voltage Serial Programming mode, the fol-
19.7.1
Enter High-voltage Serial Programming Mode
The following algorithm puts the device in High-voltage Serial Programming mode:
1.
CC
to 0V.
2.
Apply 4.5 - 5.5V between V
CC and GND. Ensure that VCC reaches at least 1.8V within
the next 20 s.
3.
Wait 20 - 60 s, and apply 11.5 - 12.5V to RESET.
4.
Keep the Prog_enable pins unchanged for at least 10 s after the High-voltage has
been applied to ensure the Prog_enable Signature has been latched.
5.
Release the Prog_enable[2] pin after t
HVRST has elapsed.
6.
Wait at least 300 s before giving any serial instructions on SDI/SII.
7.
Exit Programming mode by power the device down or by bringing RESET pin to 0V.
If the rise time of the V
CC is unable to fulfill the requirements listed above, the following alterna-
tive algorithm can be used:
1.
CC
to 0V.
2.
Apply 4.5 - 5.5V between V
CC and GND.
3.
Monitor V
CC, and as soon as VCC reaches 0.9 - 1.1V, apply 11.5 - 12.5V to RESET.
4.
Keep the Prog_enable pins unchanged for at least 10 s 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
RESET Pin High-voltage Threshold
Minimum High-voltage Period for
Latching Prog_enable
V
CC
V
HVRST
t
HVRST
4.5V
11.5V
100 ns
5.5V
11.5V
100 ns