MIC3003 datasheet(36/75 Pages) MICREL

36 / 75 page

Micrel, Inc.

MIC3003

November 2009

M9999-111209-C

hbwhelp@micrel.com or (408) 955-1690

Figure 19. Successfully Clearing a Fault Condition

Figure 20. Unsuccessful Attempt to Clear a Fault

Warm Resets

The MIC3003 can be reset to its power-on default state

during operation by setting the RST bit in OEMCFG0.

When this bit is set, TXFAULT and RXLOS will be de-

asserted, all registers will be restored to their normal

power-on default values, and any A/D conversion in

progress will be halted and the results discarded. The

state of the MIC3003 following this operation is

indistinguishable from a power-on reset.

Power-On Hour Meter

The Power-On Hour meter logs operating hours using an

internal real-time clock and stores the result in NVRAM.

The hour count is incremented at ten-hour intervals in the

middle of each interval. The first increment therefore

takes place five hours after power-on. Time is

accumulated whenever the MIC3003 is powered. The

hour meter’s time base is accurate to +/-10% over all

MIC3003 operating conditions, and is accurate to +/-5%

in the range 0 to 70 degrees C. The counter is capable of

storing counts of more than thirty years, but is ultimately

limited by the write-cycle endurance of the non-volatile

memory. This implies a range of at least twenty years.

Actual results will depend upon the operating conditions

and write-cycle endurance of the part in question.

Two registers, POHh and POHl, contain a 15-bit power-on

hour measurement and an error flag, POHFLT. Great care

has been taken to make the MIC3003’s hour meter immune

to data corruption and to insure that valid data is maintained

across power cycles. The hour meter employs multiple data

copies and error correction codes to maintain data validity.

This data is stored in the POHDATA registers. If POHFLT is

set, however, the power-on hour meter data has been

corrupted and should be ignored.

It is recommended that a two-byte sequential read

operation be performed on POHh and POHl to insure

coherency between the two registers. These registers are

accessible by the OEM using a valid OEM password. The

only operation that should be performed on these registers

is to clear the hour meters initial value, if necessary, at the

time of product shipment. The hour meter result may be

cleared by setting all eight POHDATA bytes to 00h.

MIC3003 数据表(PDF) 36 Page - Micrel Semiconductor

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