ATMEGA64A-MU Atmel, ATMEGA64A-MU Datasheet - Page 18

• Manufacturer Part Number: ATMEGA64A-MU
• Description: MCU 8-Bit ATmega AVR RISC 64KB Flash 3.3V/5V 64-Pin MLF EP
• Manufacturer: Atmel

Specifications of ATMEGA64A-MU

• Package: 64MLF EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 16 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 53
• Interface Type: SPI/USART
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 4
• Ram Size: 4 KB
• Program Memory Size: 64 KB
• Program Memory Type: Flash
• Operating Temperature: -40 to 85 °C

9. Errata
9.1
8160CS–AVR–07/09
ATmega64A, rev. D
The revision letter in this section refers to the revision of the ATmega64A device.
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1. First Analog Comparator conversion may be delayed
2. Interrupts may be lost when writing the timer registers in the asynchronous timer
3. Stabilizing time needed when changing XDIV Register
First Analog Comparator conversion may be delayed
Interrupts may be lost when writing the timer registers in the asynchronous timer
Stabilizing time needed when changing XDIV Register
Stabilizing time needed when changing OSCCAL Register
IDCODE masks data from TDI input
Reading EEPROM by using ST or STS to set EERE bit triggers unexpected interrupt request
If the device is powered by a slow rising V
take longer than expected on some devices.
Problem Fix/Workaround
When the device has been powered or reset, disable then enable theAnalog Comparator
before the first conversion.
The interrupt will be lost if a timer register that is synchronous timer clock is written when the
asynchronous Timer/Counter register (TCNTx) is 0x00.
Always check that the asynchronous Timer/Counter register neither have the value 0xFF nor
0x00 before writing to the asynchronous Timer Control Register (TCCRx), asynchronous
Timer Counter Register (TCNTx), or asynchronous Output Compare Register (OCRx).
After increasing the source clock frequency more than 2% with settings in the XDIV register,
the device may execute some of the subsequent instructions incorrectly.
Problem Fix / Workaround
The NOP instruction will always be executed correctly also right after a frequency change.
Thus, the next 8 instructions after the change should be NOP instructions. To ensure this,
follow this procedure:
1.Clear the I bit in the SREG Register.
2.Set the new pre-scaling factor in XDIV register.
3.Execute 8 NOP instructions
4.Set the I bit in SREG
This will ensure that all subsequent instructions will execute correctly.
Assembly Code Example:
CLI
OUT
NOP
NOP
NOP
NOP
NOP
NOP
Problem Fix / Workaround
XDIV, temp
; clear global interrupt enable
; set new prescale value
; no operation
; no operation
; no operation
; no operation
; no operation
; no operation
CC
, the first Analog Comparator conversion will
ATmega64A
18