Texas Instruments MSC1210 - Manual (Page 128)

Tone Generator
11-4
11.2.1 Tone Generator Waveforms
When TPCNTL[1:0] = 11, the output of the tone generator may be either a stair-
case waveform or a square waveform depending on the configuration of
TPCNTL.2.
When TPCNTL.2 is 1, a staircase waveform is generated that will have three
levels: DGND, tristate, and V
DD
volts.
When the TPCNTL.2 is 0, a square waveform of 50% duty cycle is generated
that will have two levels: DGND and V
DD
volts.
11.2.1.1 Staircase Mode
When TPCNTL.2 is 1 (i.e., TPCNTL[2:0] = 111), a staircase waveform is gener-
ated, as shown in Figure 11−3. In this figure, the value of PWM Period = 18F
H
,
which is equal to 399. Therefore, the total time period is equal to 800 T
BASE
.
11.2.1.2 Square Mode
When TPCNTL.2 is ‘0’ (i.e., TPCNTL[2:0] = ‘011’), a square waveform is gen-
erated. An example with PWM Period = 2 is shown in Figure 11−4. We get a
50 % duty cycle square wave with a period of (2
S PWM Period).
Figure 11−3. Timing Diagram of Tone Generator in Staircase Mode
Figure 11−4. Timing Diagram of Tone Generator in Square Wave Mode