Texas Instruments TMS320C3x - Manual (Page 390)

Timers
12-11 Peripherals
12.1.6.2 CLKSRC = 1 and FUNC = 1
If CLKSRC = 1 and FUNC = 1 (see Figure 12–6), the timer input comes from
the internal clock, and the timer output goes to TCLK. This value can be inverted
using INV, and you can read in DATIN the value output on TCLK.
Figure 12–6. Timer Configuration with CLKSRC = 1 and FUNC = 1
In
Out
Timer
Internal
clock
TCLK
TSTAT DATIN
CLKSRC = 1 (internal)
FUNC = 1 (timer pin)
Internal External
12.1.6.3 CLKSRC = 0 and FUNC = 0
If CLKSRC = 0 and FUNC = 0 (see Figure 12–7), the timer is driven according
to the status of the I/O bit.
- If I/O = 0, the timer input comes from TCLK. This value can be inverted
using INV, and you can read in DATIN the value of TCLK. See
Figure 12–7 (a).
- If I/O = 1, TCLK is an output pin. Then, TCLK and the timer are both driven
by DATOUT. All 0-to-1 transitions of DATOUT increment the counter. INV
has no effect on DATOUT. You can read in DATIN the value of DATOUT.
See Figure 12–7 (b).
Figure 12–7. Timer Configuration with CLKSRC = 0 and FUNC = 0
In
Out
Timer
I/O port
control
TCLK
TSTAT
CLKSRC = 0 (external)
FUNC = 0 (I/O pin)
I/O = 1 (output)
(b)
Internal External
In
Out
Timer
I/O port
control
TCLK
TSTAT
CLKSRC = 0 (external)
FUNC = 0 (I/O pin)
I/O = 0 (input)
(a)
Internal External
DATIN DATOUT