SI3220 Datasheet, PDF (64/112 Pages) Silicon Laboratories – DUAL PROSLIC® PROGRAMMABLE CMOS SLIC/CODEC

Si3220/25
To enable automatic cadence for tone generator 1,
define the OSC1TA and OSC1TI registers and set the
OSC1TAEN and OSC1TIEN bits. This enables each of
the timers to control the state of the oscillator enable bit,
OSC1EN. The 16-bit counter counts until the active
timer expires, at which time the 16-bit counter resets to
zero and begins counting until the inactive timer
expires. The cadence continues until the user clears the
OSC1TA and OSC1TIEN control bits. Setting the
ZEROEN1 bit implements the zero crossing detect
feature. This ensures that each oscillator pulse ends
without a dc component. The timing diagram in
Figure 36 is an example of an output cadence that uses
the zero crossing feature.
One-shot oscillation is possible with OSC1EN and
OSC1TAEN. Direct control over the cadence is
achieved by setting the OSC1EN bit directly if
OSC1TAEN and OSC1TIEN are disabled.
The operation of tone generator 2 is identical to that of
tone generator 1 using its respective control registers.
Note: Tone Generator 2 should not be enabled simulta-
neously with the ringing oscillator because of resource
sharing within the hardware.
Table 34. Register and RAM Locations Used for Tone Generation
Parameter
Oscillator 1 Frequency
Coefficient
Oscillator 1 Amplitude Coeffi-
cient
Oscillator 1 Initial Phase
Coefficient
Oscillator 1 Active Timer
Oscillator 1 Inactive Timer
Oscillator 1 Control
Oscillator 1 Interrupts
Parameter
Oscillator 2 Frequency
Coefficient
Oscillator 2 Amplitude Coeffi-
cient
Oscillator 2 Initial Phase
Coefficient
Oscillator 2 Active Timer
Oscillator 2 Inactive Timer
Oscillator 2 Control
Oscillator 2 Interrupts
Tone Generator 1
Register/RAM
Mnemonics
Register/RAM Bits
OSC1FREQ
OSC1FREQ[15:3]
Description/Range
(LSB Size)
Sets oscillator frequency
OSC1AMP
OSC1AMP[15:0]
Sets oscillator amplitude
OSC1PHAS
OSC1PHAS[15:0]
O1TALO/O1TAHI
OSC1TA[15:0]
O1TILO/O1TIHI
OSC1TI[15:0]
OMODE, OCON
FSKSSEN, OSC1FSK,
ZEROEN1, ROUT1,
ENSYNC1, OSC1TAEN,
OSC1TIEN, OSC1EN
IRQVEC1, IRQEN1 OS1TAS, OS1TIS, OS1TAE,
OS1TIE
Tone Generator 2
Location
Register/RAM Address
OSC2FREQ
OSC2FREQ[15:3]
Sets initial phase
(default = 0)
0 to 8.19 s (125 µs)
0 to 8.19 s (125 µs)
Enables all Oscillator 1
parameters
Interrupt enable/status
Description/Range
Sets oscillator frequency
OSC2AMP
OSC2AMP[15:0]
Sets oscillator amplitude
OSC2PHAS
OSC2PHAS[15:0]
O2TALO/O2TAHI
O2TILO/O2TIHI
OMODE, OCON
IRQVEC1, IRQEN1
OSC2TA[15:0]
OSC2TI[15:0]
ZEROEN2, ROUT2,
ENSYNC2, OSC2TAEN,
OSC2TIEN, OSC2EN
OS2TAS, OS2TIS,
OS2TAE, OS2TIE
Sets initial phase
(default = 0)
0 to 8.19 s (125 µs)
0 to 8.19 s (125 µs)
Enables all Oscillator 2
parameters
Interrupt enable/status
64
Rev. 1.2