Datasheet

178
8006H–AVR–10/09
ATtiny24/44/84
Two versions of power-on reset have been implemented, as follows.
20.5.1 Standard Power-On Reset
This implementation of power-on reset existed in early versions of ATtiny24/44/84. The table
below describes the characteristics of this power-on reset and it is valid for the following devices,
only:
• ATtiny24, revision D, and older
• ATtiny44, revision C, and older
• ATtiny84, revision A
Note: Revisions are marked on the package (packages 14P3 and 14S1: bottom, package 20M1: top)
Note: 1. Values are guidelines, only
2. Threshold where device is released from reset when voltage is rising
3. The power-on reset will not work unless the supply voltage has been below V
POA
20.5.2 Enhanced Power-On Reset
This implementation of power-on reset exists in newer versions of ATtiny24/44/84. The table
below describes the characteristics of this power-on reset and it is valid for the following devices,
only:
• ATtiny24, revision E, and newer
• ATtiny44, revision D, and newer
• ATtiny84, revision B, and newer
Note: 1. Values are guidelines, only
2. Threshold where device is released from reset when voltage is rising
3. The Power-on Reset will not work unless the supply voltage has been below V
POA
Table 20-5. Characteristics of Standard Power-On Reset. T
A
= -40 - 85°C
Symbol Parameter Min
(1)
Typ
(1)
Max
(1)
Units
V
POR
Release threshold of power-on reset
(2)
0.7 1.0 1.4 V
V
POA
Activation threshold of power-on reset
(3)
0.05 0.9 1.3 V
SR
ON
Power-on slope rate 0.01 4.5 V/ms
Table 20-6. Characteristics of Enhanced Power-On Reset. T
A
= -40 - 85°C
Symbol Parameter Min
(1)
Typ
(1)
Max
(1)
Units
V
POR
Release threshold of power-on reset
(2)
1.1 1.4 1.6 V
V
POA
Activation threshold of power-on reset
(3)
0.6 1.3 1.6 V
SR
ON
Power-On Slope Rate 0.01 V/ms