MCU AVR 32K FLASH 32TQFP

ATMEGA328P-AU

Manufacturer Part NumberATMEGA328P-AU
DescriptionMCU AVR 32K FLASH 32TQFP
ManufacturerAtmel
SeriesAVR® ATmega
ATMEGA328P-AU datasheets
 

Specifications of ATMEGA328P-AU

Core ProcessorAVRCore Size8-Bit
Speed20MHzConnectivityI²C, SPI, UART/USART
PeripheralsBrown-out Detect/Reset, POR, PWM, WDTNumber Of I /o23
Program Memory Size32KB (16K x 16)Program Memory TypeFLASH
Eeprom Size1K x 8Ram Size2K x 8
Voltage - Supply (vcc/vdd)1.8 V ~ 5.5 VData ConvertersA/D 8x10b
Oscillator TypeInternalOperating Temperature-40°C ~ 85°C
Package / Case32-TQFP, 32-VQFPProcessor SeriesATMEGA32x
CoreAVR8Data Bus Width8 bit
Data Ram Size2 KBInterface Type2-Wire, SPI, USART
Maximum Clock Frequency20 MHzNumber Of Programmable I/os23
Number Of Timers3Maximum Operating Temperature+ 85 C
Mounting StyleSMD/SMT3rd Party Development ToolsEWAVR, EWAVR-BL
Development Tools By SupplierATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKITMinimum Operating Temperature- 40 C
On-chip Adc10 bit, 8 ChannelCpu FamilyATmega
Device CoreAVRDevice Core Size8b
Frequency (max)20MHzTotal Internal Ram Size2KB
# I/os (max)23Number Of Timers - General Purpose3
Operating Supply Voltage (typ)2.5/3.3/5VOperating Supply Voltage (max)5.5V
Operating Supply Voltage (min)1.8VInstruction Set ArchitectureRISC
Operating Temp Range-40C to 85COperating Temperature ClassificationIndustrial
MountingSurface MountPin Count32
Package TypeTQFPController Family/seriesAVR MEGA
No. Of I/o's23Eeprom Memory Size1KB
Ram Memory Size2KBCpu Speed20MHz
Rohs CompliantYesFor Use WithATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVR
Lead Free Status / RoHS StatusLead free / RoHS CompliantOther namesATMEGA328P-20AU
ATMEGA328P-20AU
Q3790246
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ATmega48A/48PA/88A/88PA/168A/168PA/328/328
18.3
SS Pin Functionality
18.3.1
Slave 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.
18.3.2
Master Mode
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
the SPI becoming a Slave, the MOSI and SCK pins become inputs.
2. The SPIF Flag in SPSR is set, and if the SPI interrupt is enabled, and the I-bit in SREG is
set, the interrupt routine will be executed.
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.
18.4
Data Modes
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
and
the SCK signal, ensuring sufficient time for data signals to stabilize. This is clearly seen by sum-
marizing
Table 18-2.
SPI Mode
8271C–AVR–08/10
Figure 18-4 on page
173. Data bits are shifted out and latched in on opposite edges of
Table 18-3 on page 174
and
Table 18-4 on page
SPI Modes
Conditions
0
CPOL=0, CPHA=0
1
CPOL=0, CPHA=1
2
CPOL=1, CPHA=0
3
CPOL=1, CPHA=1
174, as done in
Table
18-2.
Leading Edge
Trailing eDge
Sample (Rising)
Setup (Falling)
Setup (Rising)
Sample (Falling)
Sample (Falling)
Setup (Rising)
Setup (Falling)
Sample (Rising)
Figure
172