LAN9250 datasheet(331/421 Pages) MICROCHIP

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DS00001913A-page 331

LAN9250

14.8.9

1588 CLOCK TEMPORARY RATE ADJUSTMENT REGISTER

(1588_CLOCK_TEMP_RATE_ADJ)

This register is used to temporarily adjust the rate of the 1588 Clock. Every 10 ns, 1588 Clock is normally incremented

by 10 ns. This register is used to occasionally change that increment to 9 or 11 ns.

Offset:

120h

Size:

32 bits

Bank:

Bits

Description

Type

Default

Clock Temporary Rate Adjustment Direction

(1588_CLOCK_TEMP_RATE_ADJ_DIR)

This field specifies if the 1588 Temporary Rate Adjustment causes the 1588

Clock to be faster or slower than the reference clock.

0 = slower (1588 Clock increments by 9 ns)

1 = faster (1588 Clock increments by 11 ns)

R/W

RESERVED

29:0

Clock Temporary Rate Adjustment Value

(1588_CLOCK_TEMP_RATE_ADJ_VALUE)

This field indicates a temporary adjustment to the reference clock period of

the 1588 Clock in units of 2-32ns. On each 10ns reference clock cycle, this

value is added to the 32-bit sub-nanoseconds portion of the 1588 Clock.

When the sub-nanoseconds portion wraps around to zero, the 1588 Clock

will be adjusted by 1ns (a 9 or 11 ns increment instead of the normal 10ns).

R/W

00000000h

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