ATMEGA8515-16AI Atmel, ATMEGA8515-16AI Datasheet - Page 152

• Manufacturer Part Number: ATMEGA8515-16AI
• Description: IC AVR MCU 8K 16MHZ IND 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8515-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -

Using MPCM
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ATmega8515(L)
The Multi-processor Communication mode enables several Slave MCUs to receive data
from a Master MCU. This is done by first decoding an address frame to find out which
MCU has been addressed. If a particular Slave MCU has been addressed, it will receive
the following data frames as normal, while the other Slave MCUs will ignore the
received frames until another address frame is received.
For an MCU to act as a Master MCU, it can use a 9-bit character frame format
(UCSZ = 7). The ninth bit (TXB8) must be set when an address frame (TXB8 = 1) or
cleared when a data frame (TXB = 0) is being transmitted. The Slave MCUs must in this
case be set to use a 9-bit character frame format.
The following procedure should be used to exchange data in Multi-processor Communi-
cation mode:
1. All Slave MCUs are in Multi-processor Communication mode (MPCM in UCSRA
2. The Master MCU sends an address frame, and all slaves receive and read this
3. Each Slave MCU reads the UDR Register and determines if it has been
4. The addressed MCU will receive all data frames until a new address frame is
5. When the last data frame is received by the addressed MCU, the addressed
Using any of the 5- to 8-bit character frame formats is possible, but impractical since the
Receiver must change between using n and n+1 character frame formats. This makes
full-duplex operation difficult since the Transmitter and Receiver uses the same charac-
ter size setting. If 5- to 8-bit character frames are used, the Transmitter must be set to
use two stop bit (USBS = 1) since the first stop bit is used for indicating the frame type.
Do not use Read-Modify-Write instructions (SBI and CBI) to set or clear the MPCM bit.
The MPCM bit shares the same I/O location as the TXC Flag and this might accidentally
be cleared when using SBI or CBI instructions.
is set).
frame. In the Slave MCUs, the RXC Flag in UCSRA will be set as normal.
selected. If so, it clears the MPCM bit in UCSRA, otherwise it waits for the next
address byte and keeps the MPCM setting.
received. The other Slave MCUs, which still have the MPCM bit set, will ignore
the data frames.
MCU sets the MPCM bit and waits for a new address frame from Master. The
process then repeats from 2.
2512K–AVR–01/10