TC1796
Peripheral Units (Vol. 2 of 2)
Analog-to-Digital Converter (ADC)
User’s Manual
25-9
V2.0, 2007-07
ADC, V2.0
The timer period
t
TPERIOD
can be specified within the range from microseconds up to
milliseconds according to the following equation.
(25.1)
shows the control and status of the conversion request source “Timer”.
Figure 25-5 Conversion Request Source “Timer”
Up to sixteen analog input channels can be controlled by the conversion request source
“Timer”. Setting request bit(s) in the timer trigger control register TTC enables the
generation of a conversion request for this analog input channel(s) by the timer. If
timer = 0, the contents of the timer trigger control register TTC are loaded into the timer
conversion request pending register TCRP. This triggers conversion requests for the
selected channel(s) if the gating input line TGT = 1. When the timer gating line TGT = 0,
the pending conversion requests do not take part in the arbitration cycle. The timer can
also be started by a pulse on the timer trigger input line TTR. The TTR and TGT input
connections depend on the product specific implementation of the ADC module. They
are described on
.
The contents of the timer conversion request pending register and the arbitration lock bit
are logically OR-ed. If bit STAT.AL or at least one bit is set in the timer conversion
request pending register, the arbitration participation flag AP.TP is set. This informs the
arbiter to include the conversion request source “Timer” in the arbitration.
t
TPERIOD
TRLD
20
f
ADC
-----------
×
=
MCA06008_mod
Set
Clock from Arbiter
f
TIMER
TCON.TR
Set
Write 1 to
SCON.TRS
Write 1 to
SCON.TRC
TCON.TSEN
Clear
Clear
&
Timer = 0
Timer
Unit
Timer Trigger
Input TTR
Timer Gating
Input TGT