Pulse Generator Mode - Toshiba TMPR4925 Manual

12.3.5

Pulse Generator Mode

When in the Pulse Generator mode, use Compare Register A (TMCPRAn) and Compare Register B
(TMCPRBn) to output a particular period and particular duty square wave to the TIMER[n] signal.
Setting the Timer Mode field (TMTCRn.TMODE) of the Timer Control Register to "01" sets the timer
to the Pulse Generator mode. Timer 0 and Timer 1 can be used, but Timer 2 cannot.
The initial state of the TIMER[n] signal can be set by the Flip Flop Default bit (TMPGMRn.FFI) of
the Pulse Generator Mode Register.
The TIMER[n] output signal reverses when the counter value matches the value set in Compare
Register A (TMCPRAn). The TIMER[n] output signal reverse again, clearing the counter when the
counter continues counting and the value set in Compare Register B (TMCPRBn) and the counter value
match. Consequently, a value greater than that in Compare Register A (TMCPRAn) must not be set in
Compare Register B (TMCPRBn).
Interrupts can be generated in the Pulse Generator mode as well. However, this is not standard
practice.
The Pulse Generator TMCPRA Status bit (TMTISRn.TPIAS) of the Timer Interrupt Status Register is
set when the count value matches the value of Compare Register A (TMCPRAn). Timer interrupts are
generated when the TMCPRA Interrupt Enable bit (TMPGMRn.TPIAE) of the Pulse Generator Mode
Register is set.
Similarly, the Pulse Generator TMCPRB Status bit (TMTISRn.TPIBS) of the Timer Interrupt Status
Register is set when the count value matches the value of Compare Register B (TMCPRBn). Timer
interrupts are generated when the TMCPRB Interrupt Enable bit (TMPGMRn.TPIBE) of the Pulse
Generator Mode Register is set.
Count Value
TMCPRBn
Compare Value
TMCPRAn
Compare Value
0x000000
TCE = 1
TIMER[n]
Figure 12.3.3 Operation Example of the Pulse Generator Mode
TCE = 0
TMODE1 = 01 (Pulse Generator Mode), CCS= 0 (Internal Clock)
FFI = 1 (Initial High), CRE = 0 (Counter Reset Disable)
12-6
Chapter 12 Timer/Counter
TCE = 1
Time