LTC2410_09 Datasheet, PDF (43/48 Pages) Linear Technology – 24-Bit No Latency DSTM ADC with Differential Input and Differential Reference

LTC2410
TYPICAL APPLICATIO S
Sample Driver for LTC2410 SPI Interface
The LTC2410 has a very simple serial interface that makes
interfacing to microprocessors and microcontrollers very
easy.
The listing in Figure 56 is a simple assembler routine for
the 68HC11 microcontroller. It uses PORT D, configuring
it for SPI data transfer between the controller and the
LTC2410. Figure 55 shows the simple 3-wire SPI
connection.
The code begins by declaring variables and allocating four
memory locations to store the 32-bit conversion result.
This is followed by initializing PORT D’s SPI configuration.
The program then enters the main sequence. It activates
the LTC2410’s serial interface by setting the SS output
low, sending a logic low to CS. It next waits in a loop for
a logic low on the data line, signifying end-of-conversion.
After the loop is satisfied, four SPI transfers are com-
pleted, retrieving the conversion. The main sequence ends
by setting SS high. This places the LTC2410’s serial
interface in a high impedance state and initiates another
conversion.
The performance of the LTC2410 can be verified using the
demonstration board DC291A, see Figure 57 for the
schematic. This circuit uses the computer’s serial port to
generate power and the SPI digital signals necessary for
starting a conversion and reading the result. It includes a
Labview application software program (see Figure 58)
which graphically captures the conversion results. It can
be used to determine noise performance, stability and
with an external source, linearity. As exemplified in the
schematic, the LTC2410 is extremely easy to use. This
demonstration board and associated software is available
by contacting Linear Technology.
13
SCK
12
LTC2410 SDO
CS ¹¹
68HC11
SCK (PD4)
MISO (PD2)
SS (PD5)
2410 F55
Figure 55. Connecting the LTC2410 to a 68HC11 MCU Using the SPI Serial Interface
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