MSP430G2xxx UART baud rate

Hi,

you can try to use the USCI baud rate calculator to estimate the error:

http://processors.wiki.ti.com/index.php/USCI_UART_Baud_Rate_Gen_Mode_Selection#USCI_UART_Calculator

Due to the high speed UART, I would suggest to use the highest frequency possible (16 MHz).

Anyway, as you mentioned, 192k baud is not a standard UART baud rate. If you want to use hyperterminal like software on the PC, I would suggest to use instead 115200 baud.

Hi,

Thanks for the fast reply.

Sorry for the mistake. I wanted to use for 921K as the baud rate. Can I use at this speed?

If I want to use only 921K. Is there any other replacement for the hyper terminal on PC. Can I write any program which can read data from COM port with that data rate ?

Thanks in advance

Hi,

if you refer to the device datasheet e.g. for MSP430G2x53, it specifies the fmax,BITCLK up to 2 MHz, so basically it is possible to run 921k baud. But the question is again the expected error rate. You might want to try use e.g. an external crystal which is the multiplication of 921k (you can try to google for example here - http://en.wikipedia.org/wiki/Crystal_oscillator_frequencies) and make it as the clock source of the USCI module.

For the PC side, I think you can try to look at libFTDI, since I worked with it sometime ago, and you can setup some custom baud rate. But again, this is out of the scope of this forum (TI MSP430), so you might want to do some research yourself (google is your best friend).

sai surya teja said:

Sorry for the mistake. I wanted to use for 921K as the baud rate. Can I use at this speed?

If I want to use only 921K. Is there any other replacement for the hyper terminal on PC. Can I write any program which can read data from COM port with that data rate ?

In TI device datasheet is noted 1 Mbps as max UART BR, but I done some research on this, and it can go over 1 Mbps.

http://forum.43oh.com/topic/3413-msp430-uart-benchmark

Use external clock or DCO on frequency that will give you smallest error for target BR.

http://forum.43oh.com/topic/2640-uart-configurator

For MSP430 / PC connection on higher BR I prefer PL2303HXD that can go up to 12 Mbps with any possible BR, but MSP430x2xx + PL2303HXD probably will cost as MSP430F5510 that have integrated USB module with 1 MByte/s transfer rate.

What is the maximum baud rate supported by msp430g2553 ? Datasheet gives only minimum.

Can it support > 1382400 bps (1.318Mbps) ?

If it does not support, which Msp variant do you suggest?

Thanks in advance

sai surya teja said:

What is the maximum baud rate supported by msp430g2553 ? Datasheet gives only minimum.

Can it support > 1382400 bps (1.318Mbps) ?

Yes, it can go over 1 Mbps, you just need right BRCLK (up to 16 MHz) that will give you minimum error. My benchmark link is in last post, anyway...

slau144 MSP430x2xx Family User's Guide   18.2.6 USART Baud Rate Generation
The maximum USART baud rate is one-third the UART source clock frequency BRCLK.

Here you have my (open source) example with MSP430x2xx UART on 4 Mbps...

http://forum.43oh.com/topic/2972-sbw-msp430f550x-based-programmer/page-3#entry34398

Thank you. I figured out the maximum baud rate it can support. It can support 2.66Mbps (16MHz/6). We need to enable over sampling mode to achieve such a high baud rate.

sai surya teja said:

It can support 2.66Mbps (16MHz/6). We need to enable over sampling mode to achieve such a high baud rate.

For oversampling mode, you’ll need an input clock that is at least 16 times higher than the baudrate. Which would be 42.5MHz for 2.66MBps. Better a multiple of it. So you cannot use oversampling mode for this high baudrate. Also, on higher baudrates than 1MHz, the bit length comes into the range of the glitch detection. There’s still some headroom, but not much, so even if it will still work on your, it isn’t guaranteed for all MSPs due to manufacturing variation between batches or silicon revisions.

Sorry, my mistake. Datasheet says maximum baud rate is 16MHz/16(=1Mbps)

Will a 25MHz variant of MSP430 supports baud rate of 1382400(1.3Mbps) ? 

Thanks

sai surya teja said:

Sorry, my mistake. Datasheet says maximum baud rate is 16MHz/16(=1Mbps)

Will a 25MHz variant of MSP430 supports baud rate of 1382400(1.3Mbps) ? 

I already posted all links, including UART config tool that will generate assembler / C setup code for any baudrate. There are plenty of open source examples. (If you don't have it) you can take 12$ (fedex shipping included in price) MSP430F5529 LP and try it by yourself.

During my benchmarks, 1 GB of data are transferred at 4 Mbps without errors, but I will not give you certificated sticker for this. You can continue this discussion, but don't see any reason for this.

If not using oversampling mode, higher baudrates than CLK/16 can be achieved. The datasheet does not list an upper limit for the G2553, only what is guaranteed to work. Above may work or not, even differently for different MSPs.