cs5378 Cirrus Logic, Inc., cs5378 Datasheet - Page 61

• Manufacturer Part Number: cs5378
• Description: Low-power Single-channel Decimation Filter
• Manufacturer: Cirrus Logic, Inc.

Run - RUN
Enables the test bit stream generator.
Data Delay - DDLY[5:0]
Programs full period delays for TBSDATA, up to a
maximum of 63 bits.
Gain - TBSGAIN[23:0]
Scales the amplitude of the sine wave output and
generated impulse. Maximum 0x04FFFF, nominal
0x04B000.
17.4 TBS Data Source
An on-chip 24-bit 1024 point digital sine wave is
stored on the CS5378 which will produce the test
signal frequencies listed in Table 18. Additional
discrete test frequencies and output rates can be
programmed by varying the interpolation factor
and output rate.
DS639F1
Test Bit Stream Characteristic Equation:
(Signal Freq) * (# TBS Data) * (Interpolation + 1) = Output Rate
Example: (31.25 Hz) * (1024) * (0x07 + 1) = 256 kHz
(TBSDATA)
Frequency
125.00 Hz
125.00 Hz
10.00 Hz
10.00 Hz
25.00 Hz
25.00 Hz
31.25 Hz
31.25 Hz
50.00 Hz
50.00 Hz
Signal
Table 18. TBS Configurations Using On-chip Data
(TBSCLK)
256 kHz
512 kHz
256 kHz
512 kHz
256 kHz
512 kHz
256 kHz
512 kHz
256 kHz
512 kHz
Output
Rate
17.5 TBS Sine Wave Output
When the TMODE bit in the TBSCFG register is
low, the TBS generator operates in sine wave
mode. In this mode, sine wave data from digital fil-
ter memory is used to create a sine wave test signal
that can drive a test DAC. Sine wave frequency
and output data rate are calculated as shown by the
characteristic equation of Table 18.
The sine wave maximum ∆Σ one’s density output
from the TBS generator is set by the TBSGAIN
register. TBSGAIN can be programmed up to a
maximum of 0x04FFFF, with the TBS generator
unstable for higher amplitudes. For the CS4373
test DAC, a gain value of 0x04B000 produces an
approximately full scale sine wave output (5 V
differential).
Output Rate
Selection
(RATE)
0x4
0x5
0x4
0x5
0x4
0x5
0x4
0x5
0x4
0x5
Interpolation
Selection
(INTP)
0x0F
0x18
0x31
0x09
0x13
0x07
0x04
0x09
0x01
0x03
CS5378
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