MIC3002 Datasheet, PDF (32/65 Pages) Micrel Semiconductor – FOM Management IC with Internal Calibr ation

Micrel, Inc.
MIC3002
The internal state machine calculates a new table index
each time a new average temperature value becomes
available. This table index is derived from the average
temperature value. The table index is then converted into
a table address for each of the four look-up tables. These
operations can be expressed as:
(12)
where TAVG(n) is the current average temperature; and
TABLE_ADDRESS=INDEX+BASE_ADDRES
where BASE_ADDRESS is the physical base address of
each table, i.e., 00_h, 40_h, 80_h, or C0_h (tables reside in the
I2CADR+4h and I2CADR+6h pages of memory).
At any given time, the current table index can be read in
the LUTINDX register.
Alarms and Warning Flags
There are 20 different conditions that will cause the
MIC3002 to set one of the bits in the WARNx or ALARMx
registers. These conditions are listed in Table 22. The
less critical of these events generate warning flags by
setting a bit in WARN0 or WARN1. The more critical
events cause bits to be set in ALARM0 or ALARM1.
An event occurs when any alarm or warning condition
becomes true. Each event causes its corresponding
status bit in ALARM0, ALARM1, WARN0, or WARN1 to
be set. This action cannot be masked by the host. The
status bit will remain set until the host reads that
particular status register, a power on-off cycle occurs, or
the host toggles TXDISABLE.
If TXDISABLE is asserted at any time during normal
operation, A/D conversions continue. The A/D results for
all parameters will continue to be reported. All events will
be reported in the normal way. If they have not already
been individually cleared by read operations, when
TXDISABLE is de-asserted, all status registers will be
cleared.
Control and Status I/O
The logic for the transceiver control and status I/O is shown
schematically in Figure 13. Note that the internal drivers on
RXLOS, RATE_SELECT, and TXFAULT are all open-drain.
These signals may be driven either by the internal logic or
external drivers connected to the corresponding MIC3002
pins. In any case, the signal level appearing at the pins of
the MIC3002 will be reported in the control register status
bits.
Note that the control bits for TX_DISABLE and
RATE_SELECT and the status bits for TXFAULT and
RXLOS do not meet the timing requirements as specified in
the SFP MSA or the GBIC Specification, revision 5.5 (SFF-
8053) for the hardware signals. The speed of the serial
interface limits the rate at which these functions can be
manipulated and/or reported. The response time for the
control and status bits is given in the “Electrical
Characteristics” subsection.
July 2007
32
M9999-073107-B
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