changing baudrate over UART

Hi,

We are 2 students from Belgium, making our final thesis on a wireless communication module (demo kit eZ430-RF2500). The goal of our thesis is to sample analog signals remotely at a max frequency of about 15Khz.

Recently we faced problems when we tried to raise the baud rate over the UART interface. The reason for this increment is because of the big datastreams that we need to transfer our samples. e.g.: raise the baudrate from 9600 to 19200.

Doing so we first configured the registers of the MSP430 microprocessor to increase the baud rate. After doing this we noticed that our transferred samples didn’t match the orginal ones. Instead we get all kinds of strange characters instead of integer measurements.

Our conclusion was that we might need to program the TUSB3410 microprocessor which converts serial protocol to USB protocol (so the one on the other side of the UART interface). Is this conclusion correct?

How can we effectively modify the microprocessor’s registers to synchonise the data streams?

We didn’t find any information on TI’s website concerning this problem. We already thought of uploading a config file into the EEPROM memory of the TUSB-processor with some kind of softwaretool, but is this the best way to do so or is this necessary?

We hope someone can help us further with this problem?

Best regards,

I have the same problem. If it is the based on the serial to USB converter, this would be really bad :x

I guess we are not the only three students who deals with that problem.

I hope someone will reply to that question.

In case that dodgy TUSB really limits the baudrate, it still possible to bypass it with a MAX3223.

Eric

Hey crazy6a8seric,

nice that you replied!! We did some test and

we found out that it really is the TUSB. We mailed to TI

with this problem and we got an engineer on the line.

He needed our email, would look for the problem and look

after a solution. I will bring you the solution from TI as soon as

i have it;-)

I don’t get you point about your solution. What is the Max3223??

Best Regards

The MAX3223CPP is a TTL to Serial Converter.

THe idea is that you convert your TTL (0 à to +5V) signal from your UART MSP430 into a serial signal (-12 to +12V). The datasheet of the MAX3223 can be found there:

http://www.datasheetcatalog.com/datashe … 3223.shtml

You can order free sample…

Usually, desktops and laptops don’t embed serial port interface, so you’ll have to buy a USB to serial converter. All the conversions are done automatically, it is really easy to implement.

What are you working on with the EZ430-RF2500?

Hey Eric,

thanks for sharing you solution! I think we really need it, because i

received a solution from a TI-ingenieur. He wrote me that it’s impossible

to change the rate to a different level then 9600 because of the TUSB3410 chip’s functionality(emulation/debugging). He also spoke of putting extra

hardware. It was exactly the same solution that you gave me here.

So i think we are going in the good way:-). And yes, i also use the eZ430-RF2500:-).

Keep up the good work there in Liverpool!

Kind Regards from Belgium;-)

Hey Eric,

did you already implemented the external hardware?

We changed the RF2500u-board by a USB to RS-232 convertor

from FTDI(devicename = FT232R).

We used 4 pins from the external device(Power,ground, TX and RX).

CTS and RTS we left open. This means also that we left pin 3 and 4

in the UART open. Did didn’t seems correct because pins 3 for example

is a “#RST”. We concluded to put pin 3 and 4 also on the powersignal(3.6 volt).

We programmed the leds on the target-board in that way that if we plug in,

we know for sure that the ED joins the AP. The only thing that’s not possible is receiving and transmitting data.

What kind of voltage-level did you do putted on pin 3 and 4 of the UART? What did you putted on the powersignal(3.3 or 5 volt)?

Any suggestions would be helpfull

Best Regards