TC1796
Peripheral Units (Vol. 2 of 2)
Fast Analog-to-Digital Converter (FADC)
User’s Manual
26-23
V2.0, 2007-07
FADC, V2.0
26.1.8.1 Offset Calibration
When offset calibration is selected (GCR.CALMODE = 01
B
), the channel amplifier inputs
of the selected channel are both connected to
V
FAREF
/2. After enabling a channel
amplifier for offset calibration, a delay of minimum 5
µ
s must be respected before starting
a conversion for this channel. The conversion result must be compared by software with
the tolerated offset value (a conversion result with zero offset is equal to 512). If the
conversion result exceeds the tolerated range, bit field ACRx.CALOFF (with x specifying
the calibrated channel) can be adjusted and a new conversion can be started. The
calibration process is finished when the conversion result is in the tolerated offset range.
After switching back to normal mode for channel x, a delay of minimum 5
µ
s must be
respected before starting a new conversion for this channel.
After an offset calibration has been finished for a channel, its gain can also be calibrated.
26.1.8.2 Gain Calibration
When gain calibration is selected (GCR.CALMODE = 10
B
), the gain can be adjusted by
software to cover the complete input voltage range. The procedure is similar to the one
for the offset calibration.