ATA6613-EK Atmel, ATA6613-EK Datasheet - Page 58

• 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

6.6.6.1
6.6.7
58
Atmel ATA6612/ATA6613
128kHz Internal Oscillator
Oscillator Calibration Register – OSCCAL
The 128kHz internal Oscillator is a low power Oscillator providing a clock of 128kHz. The fre-
quency is nominal at 3V and 25 C. This clock may be select as the system clock by
programming the CKSEL Fuses to “11” as shown in
Table 6-13.
Note:
When this clock source is selected, start-up times are determined by the SUT Fuses as shown
in
• Bits 7..0 – CAL7..0: Oscillator Calibration Value
Initial Value
Read/Write
Table 6-14 on page
The Oscillator Calibration Register is used to trim the Calibrated Internal RC Oscillator to
remove process variations from the oscillator frequency. The factory-calibrated value is
automatically written to this register during chip reset, giving an oscillator frequency of
8.0 MHz at 25°C. The application software can write this register to change the oscillator
frequency. The oscillator can be calibrated to any frequency in the range 7.3 - 8.1MHz
within ±1% accuracy. Calibration outside that range is not guaranteed.
Note that this oscillator is used to time EEPROM and Flash write accesses, and these
write times will be affected accordingly. If the EEPROM or Flash are written, do not cali-
brate to more than 8.8 MHz. Otherwise, the EEPROM or Flash write may fail.
The CAL7 bit determines the range of operation for the oscillator. Setting this bit to 0 gives
the lowest frequency range, setting this bit to 1 gives the highest frequency range. The two
frequency ranges are overlapping, in other words a setting of OSCCAL = 0x7F gives a
higher frequency than OSCCAL = 0x80.
The CAL6..0 bits are used to tune the frequency within the selected range. A setting of
0x00 gives the lowest frequency in that range, and a setting of 0x7F gives the highest fre-
quency in the range. Incrementing CAL6..0 by 1 will give a frequency increment of less
than 2% in the frequency range 7.3 - 8.1MHz.
Bit
1. The frequency is preliminary value. Actual value is TBD.
128kHz Internal Oscillator Operating Modes
CAL7
R/W
7
Nominal Frequency
59.
CAL6
R/W
128kHz
6
CAL5
R/W
5
Device Specific Calibration Value
CAL4
R/W
4
CAL3
R/W
3
Table
6-13.
CAL2
R/W
2
CAL1
R/W
1
CKSEL3..0
0011
CAL0
R/W
0
9111H–AUTO–01/11
OSCCAL