ATA6613-EK Atmel, ATA6613-EK Datasheet - Page 323

• 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

6.26
6.26.1
6.26.2
9111H–AUTO–01/11
LIN Re-synchronization Algorithm
Synchronization Algorithm
Precaution Against OSCCAL Discontinuity
The possibility to change the value of OSCCAL during the Oscillator operation allows for
in-situ calibration of the slave node to entering Master frames. The principle of operation is to
measure the TBit during the SYNCH Byte and to change the calibration value of OSCCAL to
recover from local frequency drifts due to local voltage or temperature deviation. The algorithm
used for the synchronization of the internal RC oscillator is depicted in
Figure 6-130. Dichotomic Algorithm Used for LIN Slave Clock Re-synchronization
The
OSCCAL value. For one correct re-synchronization, the frequency change must be kept on
the same side of the discontinuity (no change of OSCCAL[7]). Since there will be no device
having frequency changed by more than 10% (see
to change the frequency value by more than 10%. Therefore, when calibration tries to cross
the border because of subsequent increase (or decrease) in OSCCAL values, then the routine
must be stopped.
Example: For parts operating in the lower part of the curve, if New_OSCCAL >127 then
New_OSCCAL = 127. Similar for parts operating on the high side of the discontinuity.
Figure 7-26 on page 340
Decrement
Increment
OSCCAL
OSCCAL
illustrates the on-purpose discontinuity of RC Frequency versus
-2% < Delta(TBit) < 2%
Delta(TBit) > 2%
Delta(TBit) < -2%
Measuring
actual TBit
Atmel ATA6612/ATA6613
N
N
Figure 7-24 on page
Y
STOP:
Oscillator
Calibrated
Figure
339), thus no reason
6-130.
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