ADS7807 Burr-Brown Corporation, ADS7807 Datasheet - Page 19

• Manufacturer Part Number: ADS7807
• Description: Low-Power 16-Bit Sampling CMOS ANALOG-to-DIGITAL CONVERTER
• Manufacturer: Burr-Brown Corporation

The monostable multi-vibrator in this circuit will provide
varying pulse widths for the convert pulse. The pulse
width will be determined by the external R and C values
used with the multi-vibrator. The 74HCT123N data sheet
shows that the pulse width is (0.7) RC. Choosing a pulse
FIGURE 16. DSP56000 Interface to the ADS7807.
FIGURE 17. DSP56000 Interface to the ADS7807. Processor Initiates Conversions.
SYN = 0 (Asychronous)
GCK = 1 (Gated clock)
SCD1 = 0 (SC1 is an input)
SHFD = 0 (Shift MSB first)
WL1 = 1 WL0 = 0 (Word length = 16 bits)
DSP56000
SCO
SRD
SC1
SYN = 0 (Asychronous)
GCK = 1 (Gated clock)
SCD2 = 1 (SC2 is an output)
SHFD = 0 (Shift MSB first)
WL1 = 1
Convert Pulse
DSP56000
WL0 = 0 (Word length = 16 bits)
SRD
SC2
SC0
R/C
BUSY
SDATA
DATACLK
CS
EXT/INT
BYTE
ADS7807
+5V
B1
CLR1
A1
74HCT123N
19
width as close to the minimum value specified in this data
sheet will offer the best performance. See the Starting A
Conversion section of this data sheet for details on the
conversion pulse width.
The maximum conversion rate for a 20.48MHz DSP56000
is exactly 40kHz. Note that this will not be the case for
the ADS7806. See the ADS7806 data sheet for more
information.
R
C
EXT1
EXT1
Q1
C
R
+5V
R/C
DATACLK
SDATA
CS
EXT/INT
BYTE
ADS7807
ADS7807
®