Datasheet

18
2586JS–AVR–12/06
ATtiny25/45/85
8.2.4 Rev A
•
Too high power down power consumption
• DebugWIRE looses communication when single stepping into interrupts
• PLL not locking
• EEPROM read from application code does not work in Lock Bit Mode 3
• Reading EEPROM at low frequency may not work for frequencies below 900 kHz
1. Too high power down power consumption
Three situations will lead to a too high power down power consumption. These are:
– An external clock is selected by fuses, but the I/O PORT is still enabled as an output.
– The EEPROM is read before entering power down.
– VCC is 4.5 volts or higher.
Problem fix / Workaround
– When using external clock, avoid setting the clock pin as Output.
– Do not read the EEPROM if power down power consumption is important.
– Use VCC lower than 4.5 Volts.
2. DebugWIRE looses communication when single stepping into interrupts
When receiving an interrupt during single stepping, debugwire will loose
communication.
Problem fix / Workaround
– When singlestepping, disable interrupts.
– When debugging interrupts, use breakpoints within the interrupt routine, and run into
the interrupt.
3. PLL not locking
When at frequencies below 6.0 MHz, the PLL will not lock
Problem fix / Workaround
When using the PLL, run at 6.0 MHz or higher.
4. EEPROM read from application code does not work in Lock Bit Mode 3
When the Memory Lock Bits LB2 and LB1 are programmed to mode 3, EEPROM read does
not work from the application code.
Problem Fix/Work around
Do not set Lock Bit Protection Mode 3 when the application code needs to read from
EEPROM.
5. Reading EEPROM at low frequency may not work for frequencies below 900 kHz
Reading data from the EEPROM at low internal clock frequency may result in wrong data
read.
Problem Fix/Workaround
Avoid using the EEPROM at clock frequency below 900kHz.