TC1796
Peripheral Units (Vol. 2 of 2)
General Purpose Timer Array (GPTA)
User’s Manual
24-97
V2.0, 2007-07
GPTA, V2.0
The output multiplexer group configuration is based on the following principles:
•
Each OMG is referenced with two index variables: n and g (OMGng)
•
Index n is a group number. Global timer cell groups GTCG[3:0] have the group
number 0, Local Timer Cell Groups LTCG[3:0] have the group number 1, and Local
Timer Cell Groups LTCG[7:4] have the group number 2.
•
Index g indicates the number of an I/O or output group g (g = 0-13
D
) to which the
outputs of the output multiplexer group OMGng are connected. I/O groups IOG0 to
IOG6 are assigned to index variable g = 0 to 7 and output groups OG0 to OG6 are
assigned to index variable g = 7 to 13.
The output multiplexer logic as seen for programming is shown in
this logic, always three GTC or LTC group signals are combined to one output line that
leads to the input of an I/O or output group. For example, when looking at
each of the eight output multiplexer output lines to I/O group IOG5 is connected via three
OMGn5 (n = 0, 1, 2) with the eight outputs of one GTC group (GTCG1) and two LTC
groups (LTCG1 and LTCG5).
Figure 24-64 Output Multiplexer Group (Programmer’s View)
The 1. level multiplexer is built up by three 8:1 multiplexers that are controlled in parallel
by bit field OMLn. Bit field OMGn controls the 2. level multiplexer and connects one of
the 1. level multiplexer outputs to output n. The output of the 2. level multiplexer is
connected only to the input of an I/O group or output group if bit MRACTL.MAEN is set
(multiplexer array enabled) and no reserved bit combination of OMGn is selected. If one
of these conditions is not true, the corresponding OMG output will be held at a low level.
MCA05973
MU
X
8
GTC Group
(OMG0g)
MU
X
MU
X
LTC Group
(OMG1g)
LTC Group
(OMG2g)
MU
X
010
001
000
2. Level
Mux
OMLn
OMGn
1. Level
Mux
OMCRLg
OMCRHg
(g = 0-13)
To Input of
I/O Group g or
Output Group (g-7)
MUX
0
1
MAEN
MRACTL
&
Not a reserved
OMGn bit combination
0
8
8
3
3