ATMEGA48-20MU Atmel, ATMEGA48-20MU Datasheet - Page 165
![IC AVR MCU 4K 20MHZ 5V 32-QFN](/photos/12/32/123213/atmega48-20mu_sml.jpg)
ATMEGA48-20MU
Manufacturer Part Number
ATMEGA48-20MU
Description
IC AVR MCU 4K 20MHZ 5V 32-QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA48-20MU
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
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
Processor Series
ATMEGA48x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
512 B
Interface Type
2-Wire/SPI/USART/Serial
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
23
Number Of Timers
3
Operating Supply Voltage
2.7 V to 5.5 V
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
Minimum Operating Temperature
- 40 C
On-chip Adc
8-ch x 10-bit
Controller Family/series
AVR MEGA
No. Of I/o's
23
Eeprom Memory Size
256Byte
Ram Memory Size
512Byte
Cpu Speed
20MHz
No. Of Timers
3
Rohs Compliant
Yes
Package
32MLF EP
Device Core
AVR
Family Name
ATmega
Maximum Speed
20 MHz
For Use With
ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA48-20MU
Manufacturer:
ATMEL
Quantity:
18 000
- Current page: 165 of 378
- Download datasheet (8Mb)
18.3
18.3.1
18.3.2
18.4
2545S–AVR–07/10
SS Pin Functionality
Data Modes
Slave Mode
Master Mode
When the SPI is configured as a Slave, the Slave Select (SS) pin is always input. When SS is
held low, the SPI is activated, and MISO becomes an output if configured so by the user. All
other pins are inputs. When SS is driven high, all pins are inputs, and the SPI is passive, which
means that it will not receive incoming data. Note that the SPI logic will be reset once the SS pin
is driven high.
The SS pin is useful for packet/byte synchronization to keep the slave bit counter synchronous
with the master clock generator. When the SS pin is driven high, the SPI slave will immediately
reset the send and receive logic, and drop any partially received data in the Shift Register.
When the SPI is configured as a Master (MSTR in SPCR is set), the user can determine the
direction of the SS pin.
If SS is configured as an output, the pin is a general output pin which does not affect the SPI
system. Typically, the pin will be driving the SS pin of the SPI Slave.
If SS is configured as an input, it must be held high to ensure Master SPI operation. If the SS pin
is driven low by peripheral circuitry when the SPI is configured as a Master with the SS pin
defined as an input, the SPI system interprets this as another master selecting the SPI as a
slave and starting to send data to it. To avoid bus contention, the SPI system takes the following
actions:
1. The MSTR bit in SPCR is cleared and the SPI system becomes a Slave. As a result of
2. The SPIF Flag in SPSR is set, and if the SPI interrupt is enabled, and the I-bit in SREG is
Thus, when interrupt-driven SPI transmission is used in Master mode, and there exists a possi-
bility that SS is driven low, the interrupt should always check that the MSTR bit is still set. If the
MSTR bit has been cleared by a slave select, it must be set by the user to re-enable SPI Master
mode.
There are four combinations of SCK phase and polarity with respect to serial data, which are
determined by control bits CPHA and CPOL. The SPI data transfer formats are shown in
18-3
nal, ensuring sufficient time for data signals to stabilize. This is clearly seen by summarizing
Table 18-3
the SPI becoming a Slave, the MOSI and SCK pins become inputs.
set, the interrupt routine will be executed.
and
Figure
and
Table
18-4. Data bits are shifted out and latched in on opposite edges of the SCK sig-
18-4, as done below.
ATmega48/88/168
Figure
165
Related parts for ATMEGA48-20MU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATMEGA48-20AI](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 5V 20MHZ 32-TQFP
Manufacturer:
Atmel
Datasheet:
![ATmega48](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATmega48 Automotive](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA48-20AU](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 20MHZ 5V 32TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20PU](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 20MHZ 5V 28DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20AJ](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 5V 20MHZ 32-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20MI](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 5V 20MHZ 32-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20MJ](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 5V 20MHZ 32-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20PI](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 5V 20MHZ 28-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20PJ](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K 5V 20MHZ 28-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20MMU](/photos/12/13/121311/atmega48-20mmu_tmb.jpg)
Part Number:
Description:
IC AVR MCU 4K FLASH 20MHZ 28QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA48-20MUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 4KB FLASH 20MHZ 32QFN
Manufacturer:
Atmel
Datasheet: