ATA6613-EK Atmel, ATA6613-EK Datasheet - Page 211

• Manufacturer Part Number: ATA6613-EK
• Description: BOARD DEMO LIN-MCM FOR ATA6613
• Manufacturer: Atmel

Specifications of ATA6613-EK

• Main Purpose: Interface, LIN + MCU
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ATA6613
• Primary Attributes: LIN-SBC (System-Basis-Chip) Transceiver, LIN 2.0, Voltage Regulator, Window Watchdog
• Secondary Attributes: 16 kB Flash, 4 Power Modes: Pre-Normal, Normal, Sleep, Silent, 48-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

6.17.8
9111H–AUTO–01/11
Multi-processor Communication Mode
Table 6-73.
The recommendations of the maximum receiver baud rate error was made under the assump-
tion that the Receiver and Transmitter equally divides the maximum total error.
There are two possible sources for the receivers baud rate error. The Receiver’s system clock
(XTAL) will always have some minor instability over the supply voltage range and the temper-
ature range. When using a crystal to generate the system clock, this is rarely a problem, but
for a resonator the system clock may differ more than 2% depending of the resonators toler-
ance. The second source for the error is more controllable. The baud rate generator can not
always do an exact division of the system frequency to get the baud rate wanted. In this case
an UBRRn value that gives an acceptable low error can be used if possible.
Setting the Multi-processor Communication mode (MPCMn) bit in UCSRnA enables a filtering
function of incoming frames received by the USART Receiver. Frames that do not contain
address information will be ignored and not put into the receive buffer. This effectively reduces
the number of incoming frames that has to be handled by the CPU, in a system with multiple
MCUs that communicate via the same serial bus. The Transmitter is unaffected by the
MPCMn setting, but has to be used differently when it is a part of a system utilizing the
Multi-processor Communication mode.
If the Receiver is set up to receive frames that contain 5 to 8 data bits, then the first stop bit
indicates if the frame contains data or address information. If the Receiver is set up for frames
with nine data bits, then the ninth bit (RXB8n) is used for identifying address and data frames.
When the frame type bit (the first stop or the ninth bit) is one, the frame contains an address.
When the frame type bit is zero the frame is a data frame.
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.
# (Data+Parity Bit)
10
D
5
6
7
8
9
Recommended Maximum Receiver Baud Rate Error for Double Speed Mode
(U2Xn = 1)
R
slow
94.12
94.92
95.52
96.00
96.39
96.70
(%)
R
105.66
104.92
104,35
103.90
103.53
103.23
fast
(%)
Atmel ATA6612/ATA6613
Max Total Error (%)
+5.66/-5.88
+4.92/-5.08
+4.35/-4.48
+3.90/-4.00
+3.53/-3.61
+3.23/-3.30
Recommended Max
Receiver Error (%)
±2.5
±2.0
±1.5
±1.5
±1.5
±1.0
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