ATTINY25_11 Datasheet, PDF (20/30 Pages) ATMEL Corporation – 8-bit Microcontroller with 2/4/8K Bytes In-System Programmable Flash

8.2.3
8.2.4
Rev B and C
• PLL not locking
• EEPROM read from application code does not work in Lock Bit Mode 3
• EEPROM read may fail at low supply voltage / low clock frequency
• Timer Counter 1 PWM output generation on OC1B- XOC1B does not work correctly
1. 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.
2. 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.
3. EEPROM read may fail at low supply voltage / low clock frequency
Trying to read EEPROM at low clock frequencies and/or low supply voltage may result in
invalid data.
Problem Fix/Workaround
Do not use the EEPROM when clock frequency is below 1MHz and supply voltage is below
2V. If operating frequency can not be raised above 1MHz then supply voltage should be
more than 2V. Similarly, if supply voltage can not be raised above 2V then operating fre-
quency should be more than 1MHz.
This feature is known to be temperature dependent but it has not been characterised.
Guidelines are given for room temperature, only.
4. Timer Counter 1 PWM output generation on OC1B – XOC1B does not work correctly
Timer Counter1 PWM output OC1B-XOC1B does not work correctly. Only in the case when
the control bits, COM1B1 and COM1B0 are in the same mode as COM1A1 and COM1A0,
respectively, the OC1B-XOC1B output works correctly.
Problem Fix/Work around
The only workaround is to use same control setting on COM1A[1:0] and COM1B[1:0] control
bits, see table 14-4 in the data sheet. The problem has been fixed for Tiny45 rev D.
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
• EEPROM read may fail at low supply voltage / low clock frequency
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.
20 ATtiny25/45/85
2586NS–AVR–04/11