ICS674R-01IT データシートの表示（PDF） - Integrated Circuit Systems
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ICS674R-01IT Datasheet PDF : 6 Pages
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PRELIMINARY INFORMATION
ICS674-01
User Configurable Divider
Determining (setting) the divider
The user has full control in setting the desired divide. The user should connect the appropriate divider select
input pins directly to ground (or VDD, although this is not required because of internal pull-ups) during
Printed Circuit Board layout, so that the ICS674-01 automatically produces the correct divide when all
components are soldered. It is also possible to connect the inputs to parallel I/O ports in order to change
divides.
The divides of the ICS674-01 can be determined by the following simple equations:
Divide A = DAW+2
Where
Divider A Word (DAW) = 1 to 127 (0 is not permitted).
Divide B = (DBW+8)•PD
Where
Divider B Word (DBW) = 4 to 511 (0,1,2,3, are not permitted).
Post Divider (PD) = values on Page 2
For example, suppose Divide A is desired to be 61 and Divide B is desired to be 284, then
DAW = 59, DBW = 276 and PD = 1. This means A6:A0 is 0111011, B8:B0 is
100010100 and S2:S0 is 110. Since all inputs have pull-ups, it is only necessary to ground
the zero pins, namely A6, A2, B7, B6, B5, B3, B1, B0 and S0.
MDS 674-01 A
3
Revision 033199
Printed 11/15/00
Integrated Circuit Systems • 525 Race Street • San Jose • CA • 95126 •(408)295-9800tel•(408)295-9818fax
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