attiny25v ATMEL Corporation, attiny25v Datasheet - Page 216

• Manufacturer Part Number: attiny25v
• Description: Microcontroller With 2/4/8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

27.2.4
216
ATtiny25/45/85
Rev A
4. Timer Counter 1 PWM output generation on OC1B – XOC1B does not work correctly
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1. Too high power down power consumption
2. DebugWIRE looses communication when single stepping into interrupts
3. PLL not locking
4. EEPROM read from application code does not work in Lock Bit Mode 3
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
more than 3V. Similarly, if supply voltage can not be raised above 2V then operating fre-
quency should be more than 2 MHz.
This feature is known to be temperature dependent but it has not been characterised.
Guidelines are given for room temperature, only.
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) con-
trol bits, see table 14-4 in the data sheet. The problem has been fixed for Tiny45 rev D.
Three situations will lead to a too high power down power consumption. These are:
Problem fix / Workaround
When receiving an interrupt during single stepping, debugwire will loose
communication.
Problem fix / Workaround
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.
– 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.
– 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.
– When singlestepping, disable interrupts.
– When debugging interrupts, use breakpoints within the interrupt routine, and run into
the interrupt.
2586K–AVR–01/08