TC1796
Peripheral Units (Vol. 2 of 2)
General Purpose Timer Array (GPTA)
User’s Manual 24-35 V2.0, 2007-07
GPTA, V2.0
24.2.2.5 Clock Distribution Unit (CDU)
The Clock Distribution Unit (CDU) provides all Local and Global Timer Cells with a clock
bus containing eight different clock output signals CLK[7:0] and a special LTC prescaler
clock LTCPRE. These nine clock signals are generated out of eleven clock input signals
coming from different clock sources (see Figure 24-24).
The prescalers divide the GPTA module clock f
GPTA
by a programmable 2
n
factor. Factor
n is defined by bit fields DFA02, DFA04, DFA06 and DFA07 of control register CKBCTR.
A bit field value of 15 disables the related prescaler and selects alternate sources for
clock bus lines 2, 4, 6 and 7. For clock bus line CLK2, a bit field value of 14 selects an
alternate source.
For clock bus line CLK3, the 2-bit wide bit field DFA03 of control register CKBCTR
selects one of the four available clocks.
The LTC prescaler clock LTCPRE is generated by dividing the f
GPTA
module clock by a
factor defined by the 3-bit wide bit field DFALTC of control register CKBCTR. Note that
the LTCPRE clock is not a part of the clock bus but a clock signal that is distributed
directly from the CDU to each LTC except LTC63.