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AD7813YRZ-REEL7

P1-P3P4-P6P7-P9P10-P12
AD7813
–9–
REV. C
PARALLEL INTERFACE
The parallel interface of the AD7813 is eight bits wide. The
output data buffers are activated when both CS and RD are
logic low. At this point the contents of the data register are
placed on the 8-bit data bus. Figure 15 shows the timing dia-
gram for the parallel port. As previously explained, two succes-
sive read operations must take place in order to access the 10-bit
conversion result. The first read places the 8 MSBs on the data
bus and the second read places the 2 LSBs on the data bus. The
2 LSBs appear on DB7 and DB6, with DB5–DB0 set to logic zero.
Further read operations will access the 8 MSBs and 2 LSBs of
the 10-bit ADC conversion result again. The parallel interface
of the AD7813 is reset when BUSY goes logic high. This feature
allows the AD7813 to be used as an 8-bit converter if the user
only wishes to access the 8 MSBs of the conversion. Care must
be taken to ensure that a read operation does not occur while
BUSY is high. Data read from the AD7813 while BUSY is high
will be invalid. For optimum performance the read operation
should end at least 100 ns (t
10
) prior to the falling edge of the
next CONVST.
8 MSBs
t
1
t
2
t
3
t
POWER-UP
EXT CONVST
INT CONVST
BUSY
CS/RD
DB7–DB0
2 LSBs
Figure 13. Mode 1 Operation
8 MSBs
t
1
t
3
EXT CONVST
INT CONVST
BUSY
CS/RD
DB7–DB0
t
POWER-UP
Figure 14. Mode 2 Operation
CONVST
BUSY
CS
DB7–DB0
t
2
t
3
t
1
t
4
t
6
t
7
t
5
RD
t
8
t
9
8 MSBs 2 MSBs
Figure 15. Parallel Port Timing
AD7813
–10–
REV. C
MICROPROCESSOR INTERFACING
The parallel port on the AD7813 allows the device to be inter-
faced to a range of many different microcontrollers. This section
explains how to interface the AD7813 with some of the more
common microcontroller parallel interface protocols.
AD7813 to 8051
Figure 16 shows a parallel interface between the AD7813 and
the 8051 microcontroller. The BUSY signal on the AD7813 pro-
vides an interrupt request to the 8051 when a conversion begins.
Port 0 of the 8051 may serve as an input or output port, or as in
this case when used together, may be used as a bidirectional
low-order address and data bus. The address latch enable out-
put of the 8051 is used to latch the low byte of the address dur-
ing accesses to the device, while the high-order address byte is
supplied from Port 2. Port 2 latches remain stable when the
AD7813 is addressed, as they do not have to be turned around
(set to 1) for data input as is the case for Port 0.
AD7813
*
8051*
AD0–AD7
ALE
A8–A15
RD
INT
LATCH
DECODER
DB0–DB7
CS
RD
BUSY
*
ADDITIONAL PINS OMITTED FOR CLARITY
Figure 16. Interfacing to the 8051
AD7813 to PIC16C6x/7x
Figure 17 shows a parallel interface between the AD7813 and the
PIC16C64/65/74. The BUSY signal on the AD7813 provides
an interrupt request to the microcontroller when a conversion
begins. Of the PIC16C6x/7x range of microcontrollers only the
PIC16C64/65/74 can provide the option of a parallel slave port.
Port D of the microcontroller will operate as an 8-bit wide
parallel slave port when control bit PSPMODE in the TRISE
register is set. Setting PSPMODE enables the port pin RE0
to be the RD output and RE2 to be the CS output. For this
functionality, the corresponding data direction bits of the
TRISE register must be configured as outputs (reset to 0).
See PIC16/17 Microcontroller User Manual.
PIC16C6x/7x*
PSP0–PSP7
RD
INT
*
ADDITIONAL PINS OMITTED FOR CLARITY
CS
AD7813
*
DB0–DB7
CS
RD
BUSY
Figure 17. Interfacing to the PIC16C6x/7x
AD7813 to ADSP-21xx
Figure 18 shows a parallel interface between the AD7813 and
the ADSP-21xx series of DSPs. As before, the BUSY signal on
the AD7813 provides an interrupt request to the DSP when a
conversion begins.
*
ADDITIONAL PINS OMITTED FOR CLARITY
ADDRESS
DECODE
LOGIC
EN
AD7813
*
DB0–DB7
CS
RD
BUSY
ADSP-21xx*
D7–D0
DMS
A13–A0
RD
IRQ
Figure 18. Interfacing to the ADSP-21xx
AD7813
–11–
REV. C
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
16-Lead Plastic DIP
(N-16)
16
18
9
0.840 (21.33)
0.745 (18.93)
0.280 (7.11)
0.240 (6.10)
PIN 1
SEATING
PLANE
0.022 (0.558)
0.014 (0.356)
0.060 (1.52)
0.015 (0.38)
0.210 (5.33)
MAX
0.130
(3.30)
MIN
0.070 (1.77)
0.045 (1.15)
0.100
(2.54)
BSC
0.160 (4.06)
0.115 (2.93)
0.325 (8.25)
0.300 (7.62)
0.015 (0.381)
0.008 (0.204)
0.195 (4.95)
0.115 (2.93)
16-Lead Small Outline Package
(R-16A)
16 9
81
0.3937 (10.00)
0.3859 (9.80)
0.2550 (6.20)
0.2284 (5.80)
0.1574 (4.00)
0.1497 (3.80)
PIN 1
SEATING
PLANE
0.0098 (0.25)
0.0040 (0.10)
0.0192 (0.49)
0.0138 (0.35)
0.0688 (1.75)
0.0532 (1.35)
0.0500
(1.27)
BSC
0.0099 (0.25)
0.0075 (0.19)
0.0500 (1.27)
0.0160 (0.41)
8°
0°
0.0196 (0.50)
0.0099 (0.25)
x 45°
16-Lead Thin Shrink Small Outline Package
(RU-16)
16
9
8
1
0.201 (5.10)
0.193 (4.90)
0.256 (6.50)
0.246 (6.25)
0.177 (4.50)
0.169 (4.30)
PIN 1
SEATING
PLANE
0.006 (0.15)
0.002 (0.05)
0.0118 (0.30)
0.0075 (0.19)
0.0256
(0.65)
BSC
0.0433
(1.10)
MAX
0.0079 (0.20)
0.0035 (0.090)
0.028 (0.70)
0.020 (0.50)
8°
0°
C01005–0–10/00 (rev. C)
PRINTED IN U.S.A.
P1-P3P4-P6P7-P9P10-P12

AD7813YRZ-REEL7

Mfr. #:
Buy AD7813YRZ-REEL7
Manufacturer:
Analog Devices Inc.
Description:
Analog to Digital Converters - ADC 2.7V-5.5V 400kSPS 8-/10-Bit Sampling
Lifecycle:
New from this manufacturer.
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