EVAL-AD1833AEB AD [Analog Devices], EVAL-AD1833AEB Datasheet - Page 15

• Manufacturer Part Number: EVAL-AD1833AEB
• Description: 24-Bit, 192 kHz, DAC
• Manufacturer: AD [Analog Devices]

TDM Mode Timing—Interfacing to a SHARC
In TDM mode, the AD1833A can be the master or slave, depend-
ing on Bit 0 in Control Register 3. In master mode, it generates a
frame sync signal (FSTDM) on its L/RCLK pin and a bit clock
(BCLKTDM) on its BCLK pin, whereas in slave mode it expects
these signals to be provided. These signals are used to control
the data transmission from the SHARC. The bit clock must run
at a frequency of IMCLK/2 and the interpolation mode must be
set to 8 , which limits TDM mode to frequencies of 48 kHz or
less. In this mode, all data is written on the rising edge of the bit
clock and read on the falling edge of the bit clock. The frame
starts with a frame sync at the rising edge of the bit clock. The
SHARC then starts outputting data on the next rising edge of
the bit clock. Each channel is given a 32-bit clock slot, and the
data is left-justified and uses 16, 20, or 24 of the 32 bits. An
enlarged diagram detailing this is provided (see Figure 9). The
data is sent from the SHARC to the AD1833A on the SDIN1
pin and provided in the following order: MSB first—Internal
DACL0, Internal DACL1, Internal DACL2, AUX DACL0,
Internal DACR0, Internal DACR1, Internal DACR2, and AUX
REV. 0
BCLKTDM
L/RCLK
SDATA
FSTDM
BCLK
24-BIT DATA
20-BIT DATA
16-BIT DATA
BCLKTDM
MSB
MSB
MSB
MSB
INTERNAL
DAC L0
MSB
MSB
MSB
MSB
–1
–1
–1
–1
MSB
MSB
MSB
MSB
–2
–2
–2
–2
MSB
MSB
MSB
MSB
–3
–3
–3
–3
INTERNAL
DAC L1
MSB
32 BCLKs
MSB
MSB
MSB
–4
–4
–4
–4
MSB
–5
MSB
–6
INTERNAL
DAC L2
®
LSB
LSB
LSB
+8
+4
Figure 10. DSP Mode Timing
Figure 9. TDM Mode Timing
LSB
LSB
+7
+3
LSB
LSB
AUXILIARY
+6
+2
DAC L0
LSB
LSB
+5
+1
–15–
LSB
LSB
+4
DACR0. The data is written on the rising edge of the bit clock
and read by the AD1833A on the falling edge of the bit clock.
The left and right data destined for the auxiliary DAC is sent in
standard I
and SOUT pins as the L/RCLK, BCLK, and SDATA pins,
respectively, for communicating with the auxiliary DAC.
DSP Mode Timing
DSP mode timing uses the rising edge of the frame sync signal
on the L/RCLK pin to denote the start of the transmission of a
data-word. Note that for both left and right channels, a rising
edge is used; therefore in this mode, there is no way to determine
which data is intended for the left channel and which is intended
for the right. The DSP writes data on the rising edge of BCLK
and the AD1833A reads it on the falling edge. The DSP raises
the frame sync signal on the rising edge of BCLK and then proceeds
to transmit data, MSB first, on the next rising edge of BCLK.
The data length can be 16, 20, or 24 bits. The frame sync signal
can be brought low any time at or after the MSB is transmitted,
but must be brought low at least one BCLK period before the
start of the next channel transmission.
MSB
LSB
INTERNAL
+3
DAC R0
MSB
–1
LSB
+2
2
S format in the next frame using the SDIN2, SDIN3,
MSB
–2
LSB
+1
MSB
–3
INTERNAL
LSB
DAC R1
32 BCLKs
MSB
–4
MSB
–5
MSB
–6
INTERNAL
DAC R2
AUXILIARY
AD1833A
DAC R0
MSB