TC1796
Peripheral Units (Vol. 2 of 2)
Analog-to-Digital Converter (ADC)
User’s Manual 25-15 V2.0, 2007-07
ADC, V2.0
The SW0TR and SW0GT input connections depend on the product specific
implementation of the ADC module. They are described in Section 25.3.6.2.
25.1.2.6 Parallel Conversion Request Source “Auto-Scan”
The conversion request source “Auto-scan” allows continuous conversions of a
selectable group of analog channels with almost zero software effort in generating and
controlling these conversion requests. Auto-scan provides a single conversion sequence
mode as well as continuous conversion sequence mode. Each analog channel can be
configured individually to participate in an auto-scan sequence.
Figure 25-9 Conversion Request Source “Auto-Scan”
The group of analog channels to be auto-scanned is determined by setting the
corresponding channel request flags SRQn in the auto-scan conversion request register
SCN. The auto-scan sequence is started by programming an auto-scan mode in the A/D
Converter control register (bit field CON.SCNM). Selecting an auto-scan mode loads the
contents of the auto-scan conversion request register SCN into the auto-scan
conversion request pending register ASCRP.
If at least one bit is set in the auto-scan conversion request pending register when the
auto-scan gating line ASGT = 1, the arbitration participation flag AP.ASP is set. This
informs the arbiter to include the conversion request source “Auto-scan” into the
arbitration. If “Auto-scan” is the arbitration winner, a conversion is started for the
conversion request within register ASCRP with the highest channel number. Pending
conversion requests for the auto-scan channels are processed in the sequence from the
MCA06012
SCN
ASCRP
AP.ASP
Set
Reset by Software
Clear all
on reset by
software
Set/Reset by Arbiter
Auto-Scan
Control
Unit and
Service
Request
Generation
&
Gating Input
ASGT
16
16
16
≥1
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