MC68HC908KX2 MOTOROLA [Motorola, Inc], MC68HC908KX2 Datasheet - Page 134

• Manufacturer Part Number: MC68HC908KX2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Internal Clock Generator Module (ICG)
7.8.3 ICG Trim Register
7.8.4 ICG DCO Divider Register
Technical Data
134
Address: $0038
Address: $0039
Reset:
Reset:
Read:
Read:
Write:
Write:
TRIM7:TRIM0 — ICG Trim Factor Bits
DDIV3:DDIV0 — ICG DCO Divider Control Bits
These read/write bits change the size of the internal capacitor used
by the internal clock generator. By testing the frequency of the internal
clock and incrementing or decrementing this factor accordingly, the
accuracy of the internal clock can be improved per electrical
specifications found in
Clock
frequency by 0.195 percent of the unadjusted value. Decrementing
this register by one increases the frequency by 0.195 percent. This
register cannot be written when the CMON bit is set. Reset sets these
bits to $80, centering the range of possible adjustment.
These bits indicate the number of divide-by-twos (DDIV) that follow
the digitally controlled oscillator. When ICGON is set, DDIV is
controlled by the digital loop filter. The range of valid values for DDIV
Figure 7-14. ICG DCO Divider Control Register (ICGDVR)
TRIM7
Bit 7
Bit 7
1
0
Internal Clock Generator Module (ICG)
Generator. Incrementing this register by one decreases the
Figure 7-13. ICG Trim Register (ICGTR)
= Unimplemented
TRIM6
6
0
6
0
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
TRIM5
5
0
5
0
20.10 Trimmed Accuracy of the Internal
TRIM4
4
0
4
0
U = Unaffected
TRIM3
DDIV3
U
3
0
3
TRIM2
DDIV2
U
2
0
2
TRIM1
DDIV1
U
1
0
1
MOTOROLA
TRIM0
DDIV0
Bit 0
Bit 0
U
0