DSP201 Burr-Brown Corporation, DSP201 Datasheet - Page 15

• Manufacturer Part Number: DSP201
• Description: DSP-Compatible Single/Dual DIGITAL-TO-ANALOG CONVERTERS
• Manufacturer: Burr-Brown Corporation

USING DSP201 AND DSP202
WITH TEXAS INSTRUMENTS DSP ICS
Figures 6 thru 12 show various ways to use the DSP201 and
DSP202 with DSP ICs from the Texas Instruments
TMS320Cxx series. For simplicity, all of these circuits are
based on using the TMS320Cxx in the mode where SSF
(Select Synch Format, pin 9) is tied HIGH, so that there is
an active High synchronization pulse generated by the
DSP201 or DSP202 after receiving a Convert Command.
The synchronization pulse can be changed to active Low
simply by making SSF LOW, where appropriate, without
changing basic operation of the D/As. The timing for either
synchronization mode is shown in Figure 1.
In all cases, the DSP201 and DSP202 expect to receive the
data with the MSB first, and the TMS320Cxx needs to be
programmed for this.
Figure 6 shows a circuit for using the TMS320C25 to
generate a complete analog input and analog output system
using the DSP201 plus the Burr-Brown DSP101 A/D.
Figure 7 shows how to use two TMS320C25 chips to drive
the two channels of the DSP202.
The TMS320C30 has dual serial I/O ports, which can be
used to drive the dual inputs on the DSP202, as shown in
Figure 8. This circuit can maximize the update rate for the
channels. Since the TMS320C30 can also output 32-bit
words, both channels of the DSP202 can be updated from a
single serial output port on the TMS320C30, using the
cascade mode as shown in Figure 9.
Figures 10 and 11 show complete two-channel analog input
and analog output systems consisting of three basic chips,
the TMS320C30 plus a DSP202 dual D/A and a Burr-
Brown DSP102 dual A/D. Figure 10 makes use of the dual
serial I/O ports on the TMS320C30, and is shown with the
DSP202 in the 16-bit Mode, which maximizes the possible
FIGURE 8. Using DSP202 with TMS320C30’s Dual SIO.
Conversion Rate
TMS320C30
Generator
CLKX - 0
CLKX - 1
FSX - 0
FSX - 1
DX - 0
DX - 1
NOTE: (1) Serial output is 16-bit MSB first.
TTL Bit
Clock
+5V
+5V
12
13
14
11
10
16
15
9
15
XCLK
SINA
SINB
SYNC
SSF
SWL
CASC
CONV
throughput rate on the system. Figure 11 makes use of the
32-bit word length mode in the TMS320C30 and the Cas-
cade Mode on both the DSP202 and the DSP102 to provide
two full analog I/O channels over a single serial I/O port
on the TMS320C30. Thus, up to four complete, separate
analog I/O channels could be operated using a single
TMS320C30, by making use of the second serial port.
Figure 12 shows how to use a TMS320C25 to update the
analog output of the DSP201.
USING DSP201 AND DSP202
WITH MOTOROLA DSP ICS
Figure 13 shows how to use the DSP201 with a Motorola
DSP56001. Using the DSP202 requires using two
DSP56001s, as indicated in Figure 7.
The DSP56001 needs to be programmed for transmission of
the MSB bit first with SYNC in the Bit Mode. If the
DSP56001 is programmed for 16-bit data words, SWL (pin
10) on the DSP201 or DSP202 needs to be tied HIGH to
select the 16-bit Mode. In the DSP56001 24-bit mode, the
DSP201 or DSP202 can be programmed to accept data
lengths of 16-bits (with SWL HIGH) or 18-bits (with SWL
LOW), and will ignore the trailing bits on the serial line.
For use with the Motorola DSP56001, SSF (pin 9) on the
DSP201 or DSP202 needs to be tied HIGH. This will cause
the DSP201 or DSP202 to transmit an appropriate active
High synchronization pulse on SYNC (pin 11) after a Con-
vert Command is received by the DSP201 or DSP202.
Timing is shown in Figure 1.
Even though the DSP201 or DSP202 require a minimum of
24 Bit Clock pulses between convert commands, the maxi-
mum update rate for the D/As using a 5MHz Bit Clock will
still be over 200kHz (5MHz / 24 = 208.3kHz.)
DSP202
VOUTA
VOUTB
21
5
±3V Analog Output Channel A
±3V Analog Output Channel B
DSP201/202
®