MSP430G2553: UART transmission issue over higher baudrate(115200)

Shubhendra Singh

Part Number: MSP430G2553
Other Parts Discussed in Thread: MSP-FET

hi,

I am using a MSP430G2553 customized board running it at 16 MHz(DCO) . i am sending an array of length 92, per second on UART using following segment of code.

void pheonix_send_data_to_pc(unsigned char * data , unsigned char length)

{

while(length)

{
while (!(IFG2&UCA0TXIFG));
UCA0TXBUF= *data;
data++;

length --;
}

}

sometimes i miss last for or five bytes means instead of 92 only 88 or 87 gets transmitted

sometimes complete frame gets transmitted means start of frame and end of frame gets transmitted but few bytes within last ten didn't get transmitted.

it would be great any one please explain how and why this is happening?

over 8 years ago

0 zrno soli over 8 years ago

Guru 34743 points

Who is receiving data? I don't have any problems with using MSP430G2553 for sending more than 2000 bytes, at once, on 4 Mbps...

		mov.w #WDTPW + WDTHOLD, &WDTCTL

		mov.b &CALBC1_16MHZ, &BCSCTL1
		mov.b &CALDCO_16MHZ, &DCOCTL
        
		bis.b #UCSWRST, &UCA0CTL1

		bis.b #(BIT5 + BIT4), &P3SEL	; P3.4/P3.5 = TXD/RXD
		bis.b #UCSSEL_2, &UCA0CTL1	; SMCLK

		; 16000000 Hz  4000000 bps
		mov.b #004h, &UCA0BR0
		mov.b #000h, &UCA0BR1
		bis.b #(UCBRS_0 + UCBRF_0), &UCA0MCTL

		bic.b #UCSWRST, &UCA0CTL1

		mov.w #70, R14
		mov.b #32, R15
		
Loop		bit.b #UCA0TXIFG, &IFG2
		jnc Loop
		mov.b R15, &UCA0TXBUF
		
		add.b #1, R15
		cmp.b #127, R15
		jne Loop
		
		mov.b #32, R15
		sub.w #1, R14
		jnz Loop

0 Shubhendra Singh over 8 years ago in reply to zrno soli

Intellectual 885 points

first of all thanks for such a quick reply and i apologize for not being specific.
i am communicating at 115200 baudrate and i am simply sending data to my PC while monitoring it in hyper terminal i noticed that sometimes i miss few bytes and some time complete frame doesn't get transmitted

0 zrno soli over 8 years ago in reply to Shubhendra Singh

Guru 34743 points

sasuke uchiha said:
first of all thanks for such a quick reply and i apologize for not being specific.
i am communicating at 115200 baudrate and i am simply sending data to my PC while monitoring it in hyper terminal i noticed that sometimes i miss few bytes and some time complete frame doesn't get transmitted

By question "Who is receiving data" I was not thinking on PC. What is between MSP430G2 and PC? If MSP-FET bridge is used, than transfer on some baudrates is not guaranteed.

0 Shubhendra Singh over 8 years ago in reply to zrno soli

Intellectual 885 points

no mam,
i am using USB to UART bridge (MSP FET is not in picture) in between MSP430G2 and my PC.

0 zrno soli over 8 years ago in reply to Shubhendra Singh

Guru 34743 points

I guess that new transfer of 92 bytes is started before finishing old one. Or length/data is/are changed by ISR during UART transmission.

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MSP430G2553: UART transmission issue over higher baudrate(115200)