ATMEGA48-20MI Atmel, ATMEGA48-20MI Datasheet - Page 359

• Manufacturer Part Number: ATMEGA48-20MI
• Description: IC AVR MCU 4K 5V 20MHZ 32-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48-20MI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA48-24MI; ATMEGA48-24MI

34.2
34.2.1
34.2.2
34.2.3
2545S–AVR–07/10
Errata ATmega88
Rev. D
Rev. B/C
Rev. A
The revision letter in this section refers to the revision of the ATmega88 device.
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1. Interrupts may be lost when writing the timer registers in the asynchronous timer
Not sampled.
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•
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1. Writing to EEPROM does not work at low operating voltages
2. Part may hang in reset
Interrupts may be lost when writing the timer registers in the asynchronous timer
Writing to EEPROM does not work at low Operating Voltages
Part may hang in reset
Interrupts may be lost when writing the timer registers in the asynchronous timer
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.
Problem Fix/Workaround
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).
Writing to the EEPROM does not work at low voltages.
Problem Fix/Workaround
Do not write the EEPROM at voltages below 4.5 Volts.
This will be corrected in rev. B.
Some parts may get stuck in a reset state when a reset signal is applied when the internal
reset state-machine is in a specific state. The internal reset state-machine is in this state for
approximately 10 ns immediately before the part wakes up after a reset, and in a 10 ns win-
dow when altering the system clock prescaler. The problem is most often seen during In-
System Programming of the device. There are theoretical possibilities of this happening also
in run-mode. The following three cases can trigger the device to get stuck in a reset-state:
- Two succeeding resets are applied where the second reset occurs in the 10ns window
before the device is out of the reset-state caused by the first reset.
- A reset is applied in a 10 ns window while the system clock prescaler value is updated by
software.
- Leaving SPI-programming mode generates an internal reset signal that can trigger this
case.
The two first cases can occur during normal operating mode, while the last case occurs only
during programming of the device.
ATmega48/88/168
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