Stand-Alone EVM
4-2
4.1
Stand-Alone EVM
The EVM can be used on its own. Using the EVM in this manner obliges the
user to provide a custom digital interface between the EVM and a host system.
Users are responsible for ensuring that proper timing requirements are met in
addition to providing any glue logic necessary. Users must also provide the
necessary analog interface and supply power to the EVM.
4.2
DSP Interface
Depending on the DSP that the user chooses, a number of TI DSKs are
available. DSKs are DSP Starter Kits, and provide users with a DSP starter
system. They contain all the necessary hardware and software to quickly
begin prototype construction.
4.2.1
TMS320C6711 Interface
4.2.1.1
Example Program
This section is a step-by-step description of how to use one of the example
programs supplied. The goal of the program is to display the digitized analog
input of the ADS1625 on the PC, as shown in Figure 4−7.
The hardware is setup as follows:
-
TMS320C6711 DSK
-
5−6K Interface card
-
ADS1625 EVM
Given this configuration, the hardware is assembled as shown in Figure 2.1.
The example program uses the driver files created with the Data Converter
Plug-in of Code Composer Studio
, which can be downloaded from the TI
website at
http://www.ti.com/sc/dcplug−in
. For the example programs
available with the ADS1625 EVM, the plug-in is not needed, as all the files are
provided.
The program itself performs the following steps:
-
Initialization of global variables by calling the function dc_configure() with
the settings of the ADS1625. These settings are stored in the Ads1605_1
data structure (defined in the file t1625_fn.h) which contains the
information about the physical address of the converter, the interrupt in
use and its polarity and other settings used by the driver. If the initialization
fails for any reason, an error message appears in the stdout window of
Code Composer Studio.
-
Enabling of the interrupts of the DSP.
-
Reading a block of data from the ADS1625 by calling the dc_rblock()
function (residing in the file t1625_ob.c) with the settings of the ADS1625,
the address of the memory block where the date should be written to and
the block size. Once the transfer is complete, the semaphore
Ads1625_1.xferInProgress is reset and a new transfer is initiated.
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