ATMEGA48-20MI Atmel, ATMEGA48-20MI Datasheet - Page 287

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ATMEGA48-20MI

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

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
27.2.1
27.3
27.4
2545S–AVR–07/10
Signature Bytes
Calibration Byte
Latching of Fuses
Table 27-7.
Note:
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked if
Lock bit1 (LB1) is programmed. Program the Fuse bits before programming the Lock bits.
The fuse values are latched when the device enters programming mode and changes of the
fuse values will have no effect until the part leaves Programming mode. This does not apply to
the EESAVE Fuse which will take effect once it is programmed. The fuses are also latched on
Power-up in Normal mode.
All Atmel microcontrollers have a three-byte signature code which identifies the device. This
code can be read in both serial and parallel mode, also when the device is locked. The three
bytes reside in a separate address space. For the ATmega48/88/168 the signature bytes are
given in
Table 27-8.
The ATmega48/88/168 has a byte calibration value for the internal RC Oscillator. This byte
resides in the high byte of address 0x000 in the signature address space. During reset, this byte
is automatically written into the OSCCAL Register to ensure correct frequency of the calibrated
RC Oscillator.
Low Fuse Byte
CKDIV8
CKOUT
SUT1
SUT0
CKSEL3
CKSEL2
CKSEL1
CKSEL0
Part
ATmega48
ATmega88
ATmega168
1. The default value of SUT1..0 results in maximum start-up time for the default clock source.
2. The default setting of CKSEL3..0 results in internal RC Oscillator @ 8 MHz. See
3. The CKOUT Fuse allows the system clock to be output on PORTB0. See
4. See
(3)
Table
(4)
See
page 33
on page 34
Fuse Low Byte
27-8.
Device ID
Table 8-9 on page 33
“System Clock Prescaler” on page 35
for details.
for details.
Bit No
7
6
5
4
3
2
1
0
0x000
0x1E
0x1E
0x1E
for details.
Description
Divide clock by 8
Clock output
Select start-up time
Select start-up time
Select Clock source
Select Clock source
Select Clock source
Select Clock source
Signature Bytes Address
for details.
0x001
0x92
0x93
0x94
ATmega48/88/168
Default Value
0 (programmed)
1 (unprogrammed)
1 (unprogrammed)
0 (programmed)
0 (programmed)
0 (programmed)
1 (unprogrammed)
0 (programmed)
“Clock Output Buffer”
0x002
0x0A
0x05
0x06
(1)
(2)
(2)
(2)
Table 8-8 on
(1)
(2)
287

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