ATMEGA88-20MU Atmel, ATMEGA88-20MU Datasheet - Page 361

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ATMEGA88-20MU

Manufacturer Part Number
ATMEGA88-20MU
Description
IC AVR MCU 8K 20MHZ 5V 32-QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA88-20MU

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
8KB (4K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K 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
Package
32MLF EP
Device Core
AVR
Family Name
ATmega
Maximum Speed
20 MHz
Operating Supply Voltage
3.3|5 V
Data Bus Width
8 Bit
Number Of Programmable I/os
23
Interface Type
SPI/TWI/USART
On-chip Adc
8-chx10-bit
Number Of Timers
3
Processor Series
ATMEGA8x
Core
AVR8
Data Ram Size
1 KB
Maximum Clock Frequency
20 MHz
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATAVRTS2080A, ATASTK512-EK1-IND
Minimum Operating Temperature
- 40 C
A/d Inputs
8-Channel, 10-Bit
Cpu Speed
20 MIPS
Eeprom Memory
512 Bytes
Input Output
23
Interface
SPI/TWI/USART
Memory Type
Flash
Number Of Bits
8
Package Type
32-pin MLF
Programmable Memory
8K Bytes
Timers
2-8-bit, 1-16-bit
Voltage, Range
4.5-5.5 V
Controller Family/series
AVR MEGA
No. Of I/o's
23
Eeprom Memory Size
512Byte
Ram Memory Size
1KB
No. Of Timers
3
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
34.3.3
2545S–AVR–07/10
Rev A
2. Interrupts may be lost when writing the timer registers in the asynchronous timer
1. Wrong values read after Erase Only operation
2. Part may hang in reset
Wrong values read after Erase Only operation
Part may hang in reset
Interrupts may be lost when writing the timer registers in the asynchronous timer
- 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.
Problem Fix/Workaround
The first case can be avoided during run-mode by ensuring that only one reset source is
active. If an external reset push button is used, the reset start-up time should be selected
such that the reset line is fully debounced during the start-up time.
The second case can be avoided by not using the system clock prescaler.
The third case occurs during In-System programming only. It is most frequently seen when
using the internal RC at maximum frequency.
If the device gets stuck in the reset-state, turn power off, then on again to get the device out
of this state.
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).
At supply voltages below 2.7V, an EEPROM location that is erased by the Erase Only oper-
ation may read as programmed (0x00).
Problem Fix/Workaround
If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write opera-
tion with 0xFF as data in order to erase a location. In any case, the Write Only operation can
be used as intended. Thus no special considerations are needed as long as the erased loca-
tion is not read before it is programmed.
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:
ATmega48/88/168
361

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