External Interface with ADS1232ref kit

Thanks Bob for replying.

We actually want to use the data from the weighing scale for another application which uses a MSP430 MCU (and has a RS-232 external interface), hence we wish to interface these two. Can you be more specific about the additional connections to be made to the ADS1232REF kit in order to interface. A schematic about the same illustrating the connections would be helpful.

GV,

Are you using a MSP430 kit that you want to connect to the ADS1232REF?  Most of the kits have some method of delivering data to the PC.  If you can give me some further information as to what devices/kit you want to use, then I can be more helpful about how to connect it.

Best regards,

Bob B

We wish to connect it to MSP430FG4618/F2013 Experimenter’s Board.

GV,

Ok, communications to a PC is easily accomplished by using the RS232 serial connection to your PC.  If your PC does not have a RS232 serial connector, you can purchase a RS232 to USB converter cable.

Choice 2 would be to connect the UCA0RXD and UCAOTXD signals of your experimenter board to the ADS1232REF.  Cut the traces from the MSP430 that connect to the MCUTX and MCURX test point holes of the ADS1232REF and wire your connections there from the experimenter board.  I can't tell you where to actually connect the wires on the experimenter board.  Maybe to R9 and R2.  You may actually want to remove R9 and R2 and connect the wire to the pad so that the current circuit does not interfere.

Best regards,

Bob B

that seems to be a good solution.
May I know what kind of code must be written at the both TXboard (ADS1232) and the RXboard(MSP430FG4618/F2013) for proper syncronization and  data acquizition 

GV,

There are two forms of communication.  One from the ADS1232 itself which will require all the signals shown in the schematic.  The SPI communications(SCLK, MOSI and MISO) must be connected to complete the communication.  The ADS1232 does not have a chip select, so no other device can be connected to the bus.  You should also use the DRDY/DOUT data line as an interrupt to your processor ( this means you tie the line to both MISO and a port pin that allows for an interrupt).  When DRDY goes low, the data results are ready to be read out.

The second communication is from the processor to the PC which is done via the method last discussed.  The TUSB3410 will respond all by itself to the baud rate from your processor.  All you need to do is properly set up the baud rate and communication as per desired.

What I have done in the past is set up an interrupt routine that gets the code from the ADS and then immediately sends it out the serial port before re-enabling the interrupt.

Best regards,

Bob B

Can you be more clear about the second way of communoation i.e via TUSB3410.
I've ADS1232REFkit (Transmitter) and MSP430FG4618/F2013 Experimenter's Board(Receiver) and not PC.

 what are the connections to be made precisely and program required at the processor side

 of both Transmitter and Receiver.

GV,

Initially you stated that you wanted to use a terminal program to see your data.  I feel like we're going around in circles.  Send me a block diagram of what you want to accomplish and I'll try to help you.

Best regards,

Bob B

GV,

Here is one option.  I already told you how to synchronize the data.  As for as the programs required, you will have to write them.

Good luck,

Bob B

Thanks a lot Bob.

Bob i had another doubt in above figure given , how can we assign two clocks to the sclk pin of ads123ref . since one as shown is from mspfg461( ie experimenter board ) and the other is by default connected from another msp430 present on the ads123ref board . 

Prem,

Welcome to the forum!  If you read my first response you will see that you need to cut the traces near the test point holes on the ADS1232REF board that connect to the on board MSP430F449.  The two microprocessors must be totally isolated so that they do not interfere with each other and there are not two outputs tied together, such as the SCLKs.

Best regards,

Bob B

Thanks  bob ,

              but how can i take the weight measured by ads123ref  board  to my experimenter board which can be used  in my application on experimenter board (MSP430FG4618/F2013).

Precisely what i need is, i need to use the weight of an object measured by ads123ref board  in my application running on experimenter board . how can i interface the two boards such that  it should not disturb the ads123ref functionality .

Prem,

Please carefully read this entire post.  You will need to communicate directly to the ADS1232 itself, or take the information from the on board MSP430.  The ADS1232REF is a reference design.  If you want to alter the design, you can do so but it is not going to be directly supported.  You will need to write your own code and interface appropriately.

It may be possible to communicate in another way using the serial communication port from the experimentor board and connect to MCURX and MCUTX test points.  In this case you can leave the on board MSP430F449 as is and communicate through the serial port.  You will need to use the command set as it is described in the ADS1232REF User's Guide.  If you  try to use this method you will need to disconnect the TUSB3410 device from the connections by cutting the traces that connect to ISO isolation devices shown in the schematic.  A note of information about this method is you will still have to write code to change the output code represented by ASCII to weight.  The serial port does not send out a weight value but rather the result code from the ADS1232.

In my opinion it would be easier to use the first method of cutting all on board MSP430 traces to the ADS1232 and connecting the experimenter's board directly.  It involves more wires but it will be much easier to capture the data and manipulate it.

Best regards,

Bob B

That clears a lot of thing. thanks.

I would prefer to go with the second option. As I need the custom setting already available in ads1232ref so that I can adjust the tear weight and so on.

Can you tell where can we find the source code on how these MCUTX and MUCRX are configured.

 Is there any standard procedure (a subroutine) on how to start a communication with an external MCU with these test points.

Prem,

On page18 in section 5 is all the information regarding the serial operation.  In particular, section 5.1 contains the serial communication parameters.  There is one thing I don't think you fully understand.  The output data is a hexadecimal representation of the direct output of the ADS1232.  It has not been converted to a weight, nor is it affected by any calibration, or adjusted by a tare.  In other words, you can press all the buttons on the ADS1232REF while it is in scale mode, but you will never see anything like what appears on the LCD display.  If you think that by using this board there will be a short cut to displaying weight, or manipulating weight information you would be quite wrong.  You will not be able to use any of the scale features of the ADS1232REF outside of the board's designed purpose.  Any features, like tare, calibration and conversion to a weight will have to be done on your micro on the experimenter's board.

If I'm understanding correctly, you will need to build your own program and hardware interface for the experimenter's board that will take the output data from the ADS1232 (which is a code representation of the analog input based on the reference voltage) and convert it to a voltage in accordance to the LSB size.  From there you would need to calibrate and convert to a weight base on the connected load cell.  As far as design information, you may find this link helpful to understand the overall design of weigh scale.

http://www.ti.com/ww/en/industrial/sensors/weigh/index.html

Best regards,

Bob B