LTC2410 Linear Technology, LTC2410 Datasheet - Page 39

• Manufacturer Part Number: LTC2410
• Description: 24-Bit No Latency ADC with Differential Input and Differential Reference
• Manufacturer: Linear Technology

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 55 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 54 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.
TYPICAL APPLICATIO S
Figure 54. Connecting the LTC2410 to a 68HC11 MCU Using the SPI Serial Interface
U
LTC2410
SDO
SCK
CS
13
12
11
The performance of the LTC2410 can be verified using the
demonstration board DC291A, see Figure 56 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 57)
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.
SCK (PD4)
MISO (PD2)
SS (PD5)
68HC11
2410 F54
LTC2410
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