Pwt Frequency Control Register (Frc); Pwt Volume Control Register (Vrc); Pwt General Control Register (Gcr); Pwt Programming - Texas Instruments OMAP5910 Technical Reference Manual

Pulse-Width Tone
Table 7–45. PWT Frequency Control Register (FRC) – Offset address (hex): 0x00
Bit Name
5–2 FRQ
1–0 OCT
Table 7–46. PWT Volume Control Register (VRC) – Offset address (hex): 0x04
Bit Name
6–1 VOL
0 ONOFF
Table 7–47. PWT General Control Register (GCR) – Offset address (hex): 0x08
Bit Name
1 TESTIN
0 CLK_EN
7.7.4

PWT Programming

7.7.4.1 Buzzer Frequency
7-54
Function
Frequency selection (12 frequencies)
Resynchronized writing, asynchronous reading
Octave selection
Resynchronized writing, asynchronous reading
Function
Volume selection
Resynchronized writing, asynchronous reading
Switch ON/OFF tone (on: 1, off: 0).
Resynchronized writing, asynchronous reading
Function
Divider 1/154 switched ON/OFF (on: 0, off: 1).
Asynchronous writing and reading
PWT clock enable (clock disabled: 0, clock enabled: 1).
Asynchronous writing and reading
To obtain the required frequencies, the PWT clock is divided in a special way.
Four frequency dividers with the coefficients
connected in series and can be enabled with the four frequency selection bits
(FRQ) in the frequency register. If a divider is not enabled, the clock passes
through the divider without any change so different frequencies can be
produced. After this a multiplexer can choose between this clock, divided by
2/4/8 or 16. The frequency is always halved (this unit is called an octave). Due
to this, the PWT has a range of four octaves.
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
101 49 50
and
/ , / , /
,
107 55 63
Reset
Value
0000
00
Reset
Value
000000
0
Reset
Value
0
0
80
are
/
127