aduc7033bstz-8l-rl Analog Devices, Inc., aduc7033bstz-8l-rl Datasheet - Page 70

• Manufacturer Part Number: aduc7033bstz-8l-rl
• Description: Integrated Precision Battery Sensor For Automotive
• Manufacturer: Analog Devices, Inc.

ADuC7033
User code then reads back the value of the low power oscillator
calibration counter. There are three possible scenarios:
•
•
•
When the OSC0TRM is changed, the routine should be run
again and the new frequency checked.
Using the internal, precision 131 kHz oscillator, it takes
approximately 4 ms to execute the calibration routine. If the
external 32.768 kHz crystal is used, the time increases to 16 ms.
Prior to the clock calibration routine being started, it is required
that the user switch to either the precision 131 kHz oscillator or
the external 32.768 kHz watch crystal to serve as the PLL clock
source. If this is not done, the PLL can lose lock each time
OSC0TRM is modified. This increases the length of time it
takes to calibrate the low power oscillator.
OSC0VAL0 = OSC0VAL1. No further action is required.
OSC0VAL0 > OSC0VAL1. The low power oscillator is
running slow. OSC0TRM must be decreased.
OSC0VAL0 < OSC0VAL1. The low power oscillator is
running fast. OSC0TRM must be increased.
OSC0VAL0 < OSC0VAL1
INCREASE
OSC0TRM
Figure 30. OSC0TRM Calibration Routine
NO
OSC0VAL0 = OSC0VAL1
IS ERROR WITHIN
DESIRED LEVEL?
OSC0STA[0] = 1
CALIBRATION
CALIBRATION
ROUTINE
ROUTINE
BEGIN
WHILE
END
YES
OSC0VAL0 > OSC0VAL1
DECREASE
OSC0TRM
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OSC0TRM Register
Name:
Address:
Default
Value:
Access:
Function:
Table 47. OSC0TRM MMR Bit Designations
Bit
7 to 4
3 to 0
OSC0CON Register
Name:
Address:
Default
Value:
Access:
Function:
Table 48. OSC0CON MMR Bit Designations
Bit
7 to 5
4
3
2
1
0
OSC0STA Register
Name:
Address:
Default
Value:
Access:
Function:
OSC0TRM
0xFFFF042C
0xX8
Read/write
This 8-bit register controls the low power
oscillator trim.
Description
Reserved. Should be written as zeros.
User Trim Bits.
OSC0CON
0xFFFF0440
0x00
Read/write
This 8-bit register controls the low power
oscillator calibration routine.
Description
Reserved. Should be written as 0.
Calibration Source.
Calibration Reset. Set to reset the calibration
counters and disable the calibration logic.
Set to Clear OSC0VAL1.
Set to Clear OSC0VAL0.
Calibration Enable.
OSC0STA
0xFFFF0444
0x00
Read access only
This 8-bit register gives the status of the low
power oscillator calibration routine.
Set to select external 32.768 kHz crystal.
Cleared to select internal precision 131 kHz
oscillator.
Set to begin calibration.
Cleared to abort calibration.