GX4002 Datasheet, PDF (44/74 Pages) Gennum Corporation – Dynamic on-chip power management control

Example ADC Conversion in Manual Mode
The following example illustrates how to use the ADC to read-out the supply sensor in
manual conversion mode:
1. Power-up the ADC and the supply sensor.
Register: PWRDN_REG2, Address: 161, PDADC = 0.
Register: PWRDN_REG2, Address: 161, PDSUPPLYSENSOR = 0.
2. Bring the ADC out of reset.
Register: ADC_REG0, Address: 142, ADCRESET = 0
3. Set the ADC mode of operation to manual mode.
Register: ADC_REG0, Address: 142, ADCAUTOCONVEN = 0.
Note that this must be a separate write operation than the reset exit, even though
it's the same register.
4. Set the ADC resolution to 12 bits.
Register: ADC_REG2, Address: 144, ADCRESOLUTION = 4.
5. Set the ADC conversion rate.
Register: ADC_REG2, Address: 144, ADCCLKRATE = 5 (default).
6. Select the ADC source as the supply sensor.
Register: ADC_REG1, Address: 143, ADCSRCSEL = 11 (decimal).
7. Set the ADC offset and offset mode (in this example, an offset of 0 is assumed).
Register: ADC_REG0, Address: 142, ADCOFFMODE = 0 (default).
Register: ADC_REG7, Address: 149, ADCOFFSETLO = 0.
Register: ADC_REG8, Address: 150, ADCOFFSETHI = 0.
8. Start the ADC conversion.
Register: ADC_REG3, Address: 145, ADCSTARTCONV = 1.
Note that it is not required to reset the ADCSTARTCONV to 0 before starting
another conversion. Writing a value of 1 to the ADCSTARTCONV bit again will
initiate a new conversion.
Read the ADC-done flag and output.
Register: ADC_REG4,5,6 Address: 146-148, ADCDONECONV, ADCOUTLO,
ADCOUTHI.
These three registers can be read-out as burst read. Note that it is important that the
LOW byte be read-out first, immediately followed by a HIGH byte. This is required to
ensure data consistency. The ADCDONECONV flag can be checked to confirm
successful conversion.
3.7.1.5 ADC Transfer Functions for Each Source
The following subsections show the typical transfer functions for each source that can
be read-out from ADC.
GX4002 2x2 14.025Gb/s Crosspoint Switch with Trace
Equalization and Output De-Emphasis
Data Sheet
55972 - 0
March 2012
44 of 74
Proprietary & Confidential