Texas Instruments TMS320C3x - Manual (Page 391)

Timers
12-12
12.1.6.4 CLKSRC = 0 and FUNC = 1
If CLKSRC = 0 and FUNC = 1 (see Figure 12–8), TCLK drives the timer.
- If INV = 0, all 0-to-1 transitions of TCLK increment the counter.
- If INV = 1, all 1-to-0 transitions of TCLK increment the counter. You can
read in DATIN the value of TCLK.
Figure 12–8. Timer Configuration with CLKSRC = 0 and FUNC = 1
In
Out
Timer
TCLK
TSTAT DATIN
CLKSRC = 0 (external)
FUNC = 1 (timer pin)
Internal External
12.1.7 Using TCLKx as General-Purpose I/O Pins
When FUNC = 0, TCLKx can be used as an I/O pin. Figure 12–9 and
Figure 12–10 show how the TCLKx is connected when it is configured as a
general-purpose I/O pin. In Figure 12–9, the I/O bit equals 0 and TCLK is
configured as an input pin whose value can be read in the DATIN bit. In
Figure 12–10, the I/O bit equals 1 and TCLK is configured as an output pin that
outputs the value you wrote in the DATOUT bit.
Figure 12–9. TCLK as an Input (I/O = 0)
DATOUT (NC)
DATIN
TCLK
External Internal
I/O = 0
FUNC = 0
Figure 12–10. TCLK as an Output (I/O = 1)
DATOUT
Internal
DATIN
TCLK
External
I/O = 1
FUNC = 0