MC145190DT View Datasheet(PDF) - Motorola => Freescale
Part Name
Description
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MC145190DT Datasheet PDF : 24 Pages
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ENB
NOTE NOTE
CLK
1
23
4
5
6
7
8
9
10 11
12 13
14
15
16 4
5
MSB
LSB
Din
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
0 CRYSTAL MODE, SHUT DOWN
1 CRYSTAL MODE, ACTIVE
2 REFERENCE MODE, REFin ENABLED and REFout
STATIC LOW
3 REFERENCE MODE, REFout = REFin (BUFFERED)
4 REFERENCE MODE, REFout = REFin/2
5 REFERENCE MODE, REFout = REFin/4
6 REFERENCE MODE, REFout = REFin/8 (NOTE 3)
7 REFERENCE MODE, REFout = REFin/16
OCTAL VALUE
0 0 0 0 NOT ALLOWED
0 0 0 1 R COUNTER = ÷ 1 (NOTE 6)
0 0 0 2 NOT ALLOWED
0 0 0 3 NOT ALLOWED
0 0 0 4 NOT ALLOWED
0 0 0 5 R COUNTER = ÷ 5
0 0 0 6 R COUNTER = ÷ 6
0 0 0 7 R COUNTER = ÷ 7
0 0 0 8 R COUNTER = ÷ 8
· · ··
· · ··
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1 F F E R COUNTER = ÷ 8190
1 F F F R COUNTER = ÷ 8191
NOTES:
BINARY VALUE
HEXADECIMAL VALUE
1. Bits R15 through R13 control the configurable “OSC or 4–stage divider” block (see Block Diagram).
2. Bits R12 through R0 control the “13–stage R counter” block (see Block Diagram).
3. A power–on initialize circuit forces a default REFin to REFout ratio of eight.
4. At this point, bits R13, R14, and R15 are stored and sent to the “OSC or 4–Stage Divider” block in the Block Diagram. Bits R0 through
R12 are loaded into the first buffer in the double–buffered section of the R register. Therefore, the R counter divide ratio is not altered
yet and retains the previous ratio loaded. The C and A registers are not affected.
5. At this point, bits R0 through R12 are transferred to the second buffer of the R register. The R counter begins dividing by the new ratio
after completing the rest of the present count cycle. CLK must be low during the ENB pulse, as shown. Also, see note 3 of Figure 16 for
an alternate method of loading the second buffer in the R register. The C and A registers are not affected. The first buffer of the R register
is not affected.
6. Allows direct access to reference input of phase/frequency detectors.
Figure 17. R Register Access and Format (16 Clock Cycles Are Used)
MC145190•MC145191
16
MOTOROLA
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