MIC3000 Datasheet, PDF (30/68 Pages) Micrel Semiconductor – SFP Management IC

MIC3000
Warm Resets
The MIC3000 can be reset to its power-on default state during
operation by setting the reset bit in OEMCFG0. When this bit
is set, TXFAULT and RXLOS will be deasserted, 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 MIC3000 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
MIC3000 is powered. The hour meter’s timebase is accurate
to 5% over all MIC3000 operating conditions. 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.
Micrel
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 MIC3000’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 cor-
rupted and should be ignored.
It is recommended that a two-byte (or more) sequential read
operation be performed on POHh and POHl to insure coher-
ency between the two registers. These registers are acces-
sible 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 00_h.
Error flag
Power-On Hour Result Format
High Byte, POHH
Low Byte, POHl
Elapsed Time / 10 Hours, MSB’s
Elapsed Time / 10 Hours, LSB’s
MSB
LSB
Table 18. Power-On Hour Meter Result Format
Test and Calibration Features
Numerous features are included in the MIC3000 to facilitate
development, testing, and diagnostics. These features are
available via registers in the OEM area. As shown in Table19,
these features include:
Function
Description
Control Register(s)
Analog loop-back
Provides analog visibility of op-amp and DAC outputs via the ADC
OEMCFG0
Fault comparator disable control
Disables the fault comparator
OEMCAL0
Fault comparator spin-on-channel mode Selects a single fault comparator channel
OEMCAL0
Fault comparator output read-back
Allows host to read individual fault comparator outputs
OEMRD
RSOUT, /INT read-back
Allows host to read the state of these pins
OEMRD
Inhibit EEPROM write cycles
Speeds repetitive writes to registers backed up by NVRAM
OEMCAL0
APC calibration mode
Allows direct writes to MODDAC and APCDAC
(temperature compensation not used)
OEMCAL0
Continuity checking
Forcing of RXLOS, TXFAULT, /INT
OEMCAL0
Halt A/D
Stops A/D conversions; ADC in one-shot mode
OEMCAL1
ADC idle flag
Indicates ADC status
OEMCAL1
A/D one-shot mode
Performs a single A/D conversion on the selected input channel
OEMCAL1
A/D spin-on-channel mode
Selects a single input channel
OEMCAL1
Channel selection
Selects ADC or fault comparator channel for spin-on-channel modes
OEMCAL1
LUT index read-back
Permits visibility of the LUT index calculated by the state-machine
LUTINDX
Manufacturer and device ID registers Facilitates presence detection and version control
MFG_ID, DEV_ID
Table 19. Test and Diagnostic Features
M9999-101204
30
October 2004