Hi,
I am facing a little problem with the bluetooth communication with my MSP430F479. I am using the BM70 ble module. I am trying to send two words over the transmit pin and as the buffer can only contain one byte, I am sending the Upper byte first and then the lower byte by swapping. The received first byte in the mobile app (to see the bluetooth transmitted data) is always correct that is as sent by the TX pin (using a breakpoint after each transmit to check the received byte). But for the second byte and third byte data transmitted, I am not getting the right data (it is showing wrong byte of data in the app) . The UART baud rate of the MSP430 is set 115200 Hz as the default baud rate of the BM70 ble module is also the same. I am attaching the code simulated in the IAR embedded workbench below:
#include <msp430.h>
;-------------------------------------------------------------------------------
ORG 01100h ; Program Start
;-----------------------------------------------------------------------------
RESET mov.w #0A00h,SP ; Initialize stackpointer
StopWDT mov.w #WDTPW+WDTHOLD,&WDTCTL ; Stop WDT
SetupFLL bis.b #XCAP11PF,&FLL_CTL0 ; Configure load caps
SetupP1 bis.b #03h,&P1DIR ; P1.1 and P1.2 output (LD1 output set to make the BM70 in application mode)
bis.b #03h,&P1OUT
OFIFGcheck bic.b #OFIFG,&IFG1 ; Clear OFIFG
mov.w #047FFh,R15 ; Wait for OFIFG to set again if
OFIFGwait dec.w R15 ; not stable yet
jnz OFIFGwait
bit.b #OFIFG,&IFG1 ; Has it set again?
jnz OFIFGcheck ; If so, wait some more
SetupP2 bis.b #BIT4+BIT5,&P2SEL ; P2.4,5 USCI option select
SetupUART
bis.b #UCSSEL_2,&UCA0CTL1 ; SMCLK
mov.b #09,&UCA0BR0 ; 1MHz 115200
mov.b #00,&UCA0BR1 ; 1MHz 115200
mov.b #02,&UCA0MCTL ; Modulation
bic.b #UCSWRST,&UCA0CTL1 ; **Initialize USCI state machine**
bis.b #UCA0RXIE,&IE2 ; Enable USCI_A0 RX interrupt
Mainloop mov.w #0F349h,R7 ;data to be sent
mov.w #1234h,R6 ;data to be sent
TZ1 bit.b #UCA0TXIFG,&IFG2 ; USCI_A0 TX buffer ready?
jz TZ1 ; Jump if TX buffer not ready
swpb R7 ;swapping the bytes
mov.b R7, &UCA0TXBUF ;send most significant byte
swpb R6 ; Prepare to send High Byte of Sum
TZ2 bit.b #UCA0TXIFG,&IFG2 ; USCI_A0 TX buffer ready?
jz TZ2 ; Jump if TX buffer not ready
mov.b R6, &UCA0TXBUF ; Send High Byte of Sum
swpb R6
TZ3 bit.b #UCA0TXIFG,&IFG2 ; USCI_A0 TX buffer ready?
jz TZ3 ; Jump if TX buffer not ready
swpb R6
mov.b R6, &UCA0TXBUF ; Send Low Byte of sum
LEND bis.b #LPM3+GIE,SR ; Enter LPM3, interrupts enabled
nop
;------------------------------------------------------------------------------
USCIA0RX_ISR; Echo back RXed character, confirm TX buffer is ready first
;------------------------------------------------------------------------------
TX0 bit.b #UCA0TXIFG,&IFG2 ; USCI_A0 TX buffer ready?
jz TX0 ; Jump if TX buffer not ready
;mov.b &UCA0RXBUF,&UCA0TXBUF ; TX -> RXed character
bic.w #LPM3,0(SP) ; Turn the CPU back on
reti ;
;
;------------------------------------------------------------------------------
; Interrupt Vectors
;------------------------------------------------------------------------------
ORG 0FFFEh ; RESET Vector
DW RESET ;
ORG 0FFF2h ; USCI_A0 Rx Vector
DW USCIA0RX_ISR ;
END
