TC1796
Peripheral Units (Vol. 2 of 2)
Analog-to-Digital Converter (ADC)
User’s Manual
25-21
V2.0, 2007-07
ADC, V2.0
25.1.2.7 Sequential Conversion Request Source “Channel Injection”
The conversion request source “Channel Injection” generates sequential conversion
requests for analog channels either with Wait-Inject or Cancel-Inject-Repeat
functionality. “Channel Injection” consists of the channel injection control register, the
back-up register, and the channel injection arbitration participation flag.
Figure 25-10 Conversion Request Source Channel Injection
The channel injection control register CHIN contains a conversion request bit CINREQ,
a control bit CIREN for selecting the cancel inject repeat feature, control information for
analog input group selection (GRPS) and external multiplexer settings (EMUX), control
information (RES) for resolution selection, and the channel number (CHNRIN) of the
ADC channel to be converted.
Setting the channel injection request bit CINREQ causes the arbitration participation flag
AP.CHP to be set. This informs the arbiter to include the conversion request source
“Channel Injection” into arbitration. If “Channel Injection” is the arbitration winner, a
conversion is started for the analog channel specified in the channel injection control
register CHIN. The settings of the external multiplexer and the resolution of the ADC are
also taken from this register.
Starting a conversion causes the channel injection request bit CINREQ to be cleared.
The channel injection arbitration participation flag AP.CHP is automatically cleared if the
channel injection control register and the back-up register contain no valid request.
If a currently running conversion initiated by “Channel Injection” is cancelled, the arbiter
restores the conversion information in a back-up register for this channel. In this context,
conversion information refers to the conversion request bit, the setting for the external
MCA06013
AP.CHP
Set
Reset by Software
Clear REQ
on reset
by software
CIN
REQ
CIREN
EMUX
RES
CHNR
IN
Back-up Register
CIN
REQ
CIREN
EMUX
RES
CHNR
IN
CHIN
Set/Reset
by Arbiter
Reset
by Arbiter
GRPS
GRPS
≥
1