Si3220/Si3225
Tone Generator Interrupts
requirements.
Both the active and inactive timers can generate an The register and RAM locations for caller ID generation
interrupt to signal “on/off” transitions to the software. are listed in Table 36. Caller ID data is entered into the
The timer interrupts for tone generator 1 can be 8-bit FSKDAT register. The data byte is double buffered
individually enabled by setting the OS1TAE and OS1TIE so that the Dual ProSLIC can generate an interrupt
bits. Timer interrupts for tone generator 2 are OS2TAE indicating the next data byte can be written when
and OS2TIE. A pending interrupt for each of the timers processing begins on the current data byte. The caller
is determined by reading the OS1TAS, OS1TIS, ID data can be transmitted in one of two modes
OS2TAS, and OS2TIS bits in the IRQVEC1 register.
Caller ID Generation
controlled by the O1FSK8 register bit. When
O1FSK8 = 0 (default case), the 8-bit caller ID data is
transmitted with a start bit and stop bit to create a 10-bit
data sequence. If O1FSK8 = 1, the caller ID data is
transmitted as a raw 8-bit sequence with no start or stop
bits. The value programmed into the OSC1TA register
determines the bit rate, and the interrupt rate is equal to
the bit rate divided by the data sequence length (8 or 10
bits).
The Dual ProSLIC devices generate caller ID signals in
compliance with various Bellcore and ITU specifications
as described in Table 35 by providing continuous phase
binary frequency shift keying (FSK) modulation.
Oscillator 1 is required because it preserves phase
continuity during frequency shifts whereas Oscillator 2
does not. Figure 37 illustrates a typical caller ID
transmission sequence in accordance with Bellcore
Table 35. FSK Modulation Requirements
Parameter
ITU-T V.23
1300 Hz
2100 Hz
Bellcore GR-30-CORE
1200 Hz
2200 Hz
1200 baud
Mark Frequency (logic 1)
Space Frequency (logic 0)
Transmission Rate
Table 36. Register and RAM Locations used for Caller ID Generation
Parameter
Register/RAM Register/RAM Bits
Mnemonic
Description/Range
(LSB Size)
Enable/disable
0 to 2.73 s (41.66 µs)*
Caller ID data
FSK Start & Stop Bit Enable
Oscillator 1 Active Timer
FSK Data Byte
OMODE
O1TALO/O1TAHI
FSKDAT
O1FSK8
OSC1TA[15:0]
FSKDAT[7:0]
FSK Frequency for Space
FSK Frequency for Mark
FSK Amplitude for Space
FSK Amplitude for Mark
FSK 0-1 Transition Freq, High
FSK 0-1 Transition Freq, Low
FSK 1-0 Transition Freq, High
FSK 1-0 Transition Freq, Low
FSKFREQ0
FSKFREQ1
FSKAMP0
FSKAMP1
FSK01HI
FSKFREQ0[15:3]
FSKFREQ1[15:3]
FSKAMP0[15:3]
FSKAMP1[15:3]
FSK01HI[15:3]
FSK01LO[15:3]
FSK10HI[15:3]
FSK10LO[15:3]
Audio range
Audio range
FSK01LO
FSK10HI
FSK10LO
*Note: Oscillator 1 active timer range and LSB stage valid only for FSK mode.
Rev. 1.0
63
SILICONIMAGE [ Silicon image ]
