#include  "msp430xG46x.h"

RST equ  02h;  P8.1 is Chip Select, PIN 1 => address 02h in P8OUT/P8DIR


            RSEG    CSTACK                  ; Define stack segment
            RSEG    CODE                    ; Assemble to Flash memory
;-----------------------------------------------------------------------------
RESET       mov.w    #SFE(CSTACK),SP    ;#02100h,SP; Initialize stackpointer
           
main        nop
StopWDT     mov.w   #WDTPW+WDTHOLD+WDTNMI+WDTTMSEL+WDTSSEL,&WDTCTL  ; Stop WDT
setupSVS    mov.b   #018h,&SVSCTL            ;Vth = 1.9V
setupRTC    mov.b   #30h,&RTCCTL
            bis.b   #RTCBCD,&RTCCTL
;----------------------------------------------------------------
;CONFIGURE PORT8 FOR CHIP SELECT(as GPIO-active low)
;----------------------------------------------------------------
SetupP8     mov.b   #00h,&P8SEL         ;CONFIGURE AS GPIO
            mov.b   #00000010b,&P8DIR         ;CONFIGURE P8.1 as OUTPUT for CS of FLASH                    
;----------------------------------------------------------------            
;Configure port 7 for SPI
;----------------------------------------------------------------
SetupP7    bis.b   #0Eh,&P7SEL             ; P7.3,2,1 option select as USCI_A0                                         
;----------------------------------------------------------------
;SETUP MSP430 FOR RTC INTERFACE on SPI
;----------------------------------------------------------------            
SetupSPI   bis.b   #UCSWRST,&UCA0CTL1           
;Initialize all USCI registers with UCSWRST=1          
           bis.b   #UCMST+UCSYNC+UCMSB,&UCA0CTL0;3-pin, 8-bit SPI master,MSB first
           bis.b   #UCSSEL_2,&UCA0CTL1     ; SMCLK=1 MHz
           mov.b   #255,&UCA0BR0           ; SMCLK/255
           clr.b   &UCA0BR1                ;
           clr.b   &UCA0MCTL               ; No modulation
;Clear UCSWRST
           bic.b   #UCSWRST,&UCA0CTL1      ; Initialize USCI state machine                                
;----------------------------------------------------------------------------
;WRITE INCREMENTED DATA TO PAGE 001000 IN FLASH => WRITE ENABLE+BULK ERASE then Write Enable +PAGE PROGRAM , THEN READ
;----------------------------------------------------------------------------
;  WRITE ENABLE INSTRUCTION CODE                                   
           bic.b  #RST,&P8OUT      ;MAKE CS LOW BY SETTING P8.1 LOW, SELECT SLAVE - RST = 00h
           
           mov.b  #00000110b,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE              
TX	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz TX   
           
	   mov.b  #11011000b,&UCA0TXBUF   ;  SECTOR INSTRUCTION CODE1101 1000
           ;mov.b  #11000111b,&UCA0TXBUF   ;  BULK ERASE INSTRUCTION CODE

;3 byte Address for Sector Erase- 00 00 01 - Sector 1 any address inside the sector
           
           mov.b  #00h,&UCA0TXBUF   ;              
SE1	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz SE1
           
           mov.b  #00h,&UCA0TXBUF   ;               
SE11	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz SE11
           
           mov.b  #01h,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE              
SE111	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz SE111
           
           bis.b  #RST,&P8OUT      ;MAKE CS HI
           
;   WAIT for Bulk erase(nop/monitor write in progress bit of status register)
	   mov.w   #100h,R11               ; Add time between transmissions to
Delay      dec.w   R11                     ; make sure slave can keep up
           jnz	Delay 
           
;  PAGE PROGRAM INSTRUCTION CODE
           bic.b  #RST,&P8OUT      ;MAKE CS LOW
           mov.b  #00000110b,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE
           
           mov.b  #00000010b,&UCA0TXBUF   ;  PAGE PROGRAM INSTRUCTION CODE              
TR	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz TR
           
;3 byte Address for Page Address- 00 10 00 
           
           mov.b  #00h,&UCA0TXBUF   ;              
TX1	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz TX1
           
           mov.b  #10h,&UCA0TXBUF   ;               
TX11	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz TX11
           
           mov.b  #00h,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE              
TX111	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz TX111
        
; Txn of data
                      
           mov.b  #05h,NO_OF_BYTES ; down counter   NO_OF_BYTES_WRITE
           mov.b #00h,R5;          Incremented Data to be txd
Mainloop   mov.b  R5,&UCA0TXBUF                 
TX2	   bit.b #UCA0TXIFG,&IFG2	;TX Buffer ready
	   jz TX2
           
           inc.b R5;
           dec.b NO_OF_BYTES               ;Tx 256 characters
           jnz Mainloop       

STOP       bis.b   #RST,&P8OUT     ; CS high to terminate transmission 
;----------------------------------------------------------------------------
;READ FROM FLASH - PAGE 001000 SAY 1ST BYTE
;----------------------------------------------------------------------------       
           bic.b   #RST,&P8OUT     ; CS Low to start transmission

;  READ DATA BYTE INSTRUCTION CODE             
           mov.b  #03h,&UCA0TXBUF   ;  READ DATA BYTE INSTRUCTION CODE              
loop	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz loop 
           
;3 byte Address for location(000000) to be read
           mov.b  #00h,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE              
RX1	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz RX1
           
           mov.b  #10h,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE              
RX11	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz RX11
           
           mov.b  #00h,&UCA0TXBUF   ;  WRITE ENABLE INSTRUCTION CODE              
RX111	   bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	   jz RX111
           
;  START READING DATA 
           mov.b  #05h,NO_OF_BYTES ; down counter
           
Mainloop1   mov.b  #01h,&UCA0TXBUF  ;dummy byte for reception
;TX_2	    bit.b #UCA0TXIFG,&IFG2   ;TX Buffer ready
	    ;jz TX_2            
       
RX2	   bit.b #UCA0RXIFG,&IFG2	;RX Buffer ready
	   jz RX2            
           mov.b  &UCA0RXBUF,R9
           
           dec.b NO_OF_BYTES               ;Tx 256 characters
           jnz Mainloop1       

           bis.b   #RST,&P8OUT     ; CS high to terminate transmission             
;------------------------------------------------------------------------------
            COMMON  INTVEC                  ; Interrupt Vectors
;------------------------------------------------------------------------------
            ORG     RESET_VECTOR            ; MSP430 RESET Vector
            DW      RESET                   ;
            END