SLASEI6A October 2019 – December 2019 TAS2564
PRODUCTION DATA.
The TAS2564 has two internal tone generators that can be used for pilot tone, ultrasonic tone, or diagnostic purposes. It is recommended to use PurePath™ Console 3 Software to configure the tone generators as the software will perform the necessary math for each register.
The frequency and amplitude or each generator can be set independently. Each tone generator is enabled using TGx_EN and will soft-ramp to the level set by registers TGx_AMP if corresponding register TGx_SR is set. The frequency using registers TGx_FREQ and amplitude using registers TGx_AMP. These amplitude and frequency should be set only when the tone generator is disabled. Additionally the first tone-generator can be configured to enable and disable the tone using a pin selected by TG1_PINEN pin. When enabled the pin will be logically ORed with the TG1_EN register to play the tone. This can be used for audible diagnostic tones or other alerting functions.
When the tone generator is configured to operate in pin-triggered mode, the sampling rate used in the TG1 equations should be 96 kHz. The range of frequencies that can be generated in this mode is 20 Hz to 38 kHz. For ASI bus sample rates of 192 kHz the tone generator 1 and 2 will run only at 96 kHz and this sampling rate should be used in the calculation. When not in pin trigger TG1 can generate tones up to fs/2.
The max frequency for tone generator 2 is based on the sampling rate and shown in Table 114.
TG_CLK | SETTING |
---|---|
0
|
External TDM (default) |
1
|
Internal Oscillator |
TG1_EN | TONE GENERATOR OUTPUT |
---|---|
00
|
disabled / pin trigger (default) |
01
|
enabled - play tone always |
10
|
audio level enabled |
11
|
reserved |
TG1_PINEN[1:0] | TONE GENERATOR OUTPUT |
---|---|
00
|
disabled (default) |
01
|
SDIN pin |
10
|
MCLK pin |
11
|
AD1 pin |
TG1_SR | SOFT RAMPUP |
---|---|
0
|
disabled |
1
|
enabled (default) |
The pilot tone frequency and amplitude can be programmed using the following register. The equations are used to calculate the register settings for a given gain, frequency, and audio sampling rate.
fc = frequency of the tone
fs = sampling rate
TG1_FREQ1[1-4] = 2 * cos(2 * pi * fc / fs)
TG1_FREQ2[1-4] = sin(2 * pi * fc / fs)
TG1_FREQ3[1-4] = (lcm(fs,fc) / fc) - 1
TG1_AMP = 10 ^ (dB/20)
Equations for tone generator 2 are
TG2_FREQ1[1-4] = 2 * cos(2 * pi * fc / (n*fs))
TG2_FREQ2[1-4] = sin(2 * pi * fc / (n*fs))
TG2_FREQ3[1-4] = (lcm(n*fs,fc) / fc) - n
TG2_AMP = (10 ^ (dB/20)) / 4
REGISTER | DEFAULT VALUE | DEFAULT REGISTERVALUE |
---|---|---|
TG1_FREQ1[1-4] | 0 | 0x0000 0000 |
TG1_FREQ2[1-4] | 0 | 0x0000 0000 |
TG1_FREQ3[1-4] | 0 | 0x0000 0000 |
TG1_AMP | -40 dBFS | 0x0147 AE14 |
TG2_FREQ1[1-4] | 0 | 0x0000 0000 |
TG2_FREQ2[1-4] | 0 | 0x0000 0000 |
TG2_FREQ3[1-4] | 0 | 0x0000 0000 |
TG2_AMP | -12 dBFS | 0x2026 F310 |
TG2_EN | TONE GENERATOR OUTPUT |
---|---|
0
|
disabled (default) |
1
|
enabled - play tone |
fs | n | MAX TONE FREQUENCY |
---|---|---|
96 kHz
|
1 | < fs /2 |
48 kHz, 32 kHz | 2 | < fs |
24 kHz | 4 | < 2*fs |
16 kHz, 8 kHz | 8 | < 4 * fs |
TG2_SR | SOFT RAMPUP |
---|---|
0
|
disabled |
1
|
enabled (default) |