AD7641ASTRL 데이터 시트보기 (PDF) - Analog Devices
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AD7641ASTRL Datasheet PDF : 28 Pages
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AD7641
MICROPROCESSOR INTERFACING
The AD7641 is ideally suited for traditional dc measurement
applications supporting a microprocessor, and ac signal processing
applications interfacing to a digital signal processor. The
AD7641 is designed to interface with a parallel 8-bit or 16-bit
wide interface or with a general-purpose serial port or I/O ports
on a microcontroller. A variety of external buffers can be used
with the AD7641 to prevent digital noise from coupling into the
ADC. The SPI Interface (ADSP-219x) section illustrates the use
of the AD7641 with the ADSP-219x SPI-equipped DSP.
SPI Interface (ADSP-219x)
Figure 40 shows an interface diagram between the AD7641 and
an SPI-equipped DSP, the ADSP-219x. To accommodate the
slower speed of the DSP, the AD7641 acts as a slave device and
data must be read after conversion. This mode also allows the
daisy-chain feature. The convert command can be initiated in
response to an internal timer interrupt. The 18-bit output data
are read with three SPI byte access. The reading process can be
initiated in response to the end-of-conversion signal (BUSY
going low) using an interrupt line of the DSP. The serial
peripheral interface (SPI) on the ADSP-219x is configured for
master mode (MSTR) = 1, clock polarity bit (CPOL) = 0, clock
phase bit (CPHA) = 1, and the SPI interrupt enable (TIMOD) =
00 by writing to the SPI control register (SPICLTx). It should be
noted that to meet all timing requirements, the SPI clock should
be limited to 17 Mb/s, allowing it to read an ADC result in less
than 1 μs. When a higher sampling rate is desired, it is
recommended to use one of the parallel interface modes.
DVDD
AD7641
MODE0
MODE1
EXT/INT
BUSY
CS
SDOUT
RD
SCLK
INVSCLK CNVST
ADSP-219x1
PFx
SPIxSEL (PFx)
MISOx
SCKx
PFx OR TFSx
1ADDITIONAL PINS OMITTED FOR CLARITY.
Figure 40. Interfacing the AD7641 to ADSP-219x
Rev. 0 | Page 26 of 28
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