;Correct video write sequence: send enable write: 2001a00 ;wait a MINIMUM of 35 ms for flash erase ;send frames... frame write takes about 550 us per frame ;wait at least 550 us after sending last frame ;send close write: 2000a00 ;re-enable playback: 2080a00 ;flash_memory_status ;bit 0 = 1 ACTIVE ;bit 1 = 1 ERASE ;bit 2 = 1 READ ;bit 3 = 1 WRITE ;bit 4 = 1 START ;bit 5 = 1 END WRITE ;bit 6 = 1 WRITE STATUS ;bit 7 = 1 VIDEO BUFFER 1/2 select ;time values @ 64 mhz, Fosc/16 ;WRITE '00011001'writes contents of led_register to 48 bytes of flash pointed at by frame_pointer_0,1,2, ;time= ~550 us ;READ '00010101'writes contents of flash to 48 bytes of RAM, one of two banks, video_buffer_1 ;READ '10010101'writes contents of flash to 48 bytes of RAM, one of two banks, video_buffer_2 ;time= ~400 us ;ERASE '00010011'ERASES entire chip- poll ERASE BIT or ACTIVE for done. ;time= ~35 ms ;WRITE STATUS '01000001'writes 0x00 to status register- enables full write to chip. ;time= ~ 10 us ;frame_pointer is NOT corrupted by this routine. ;frame_pointer is multiplied by 48 to create memory pointer ;Uses FSR2! flash_memory_routine btfss flash_memory_status,0 ;test ACTIVE bit return btfsc flash_memory_status,1 ;test ERASE bit bra erase_mode btfsc flash_memory_status,2 ;test READ bit bra read_mode btfsc flash_memory_status,3 ;test WRITE bit bra write_mode btfsc flash_memory_status,6 ;test WRITE STATUS bit bra write_status clrf flash_memory_status ;illegal, clear and return return ;************************************************************** erase_mode btfss flash_memory_status,4 ;test START bit bra run_erase ;poll for busy bit clear = DONE bcf LATD,7 ;set /CE LOW, Enable movlw 0x06 ;WREN - write enable call send_spi bsf LATD,7 ;set /CE HIGH, Disable nop nop nop bcf LATD,7 ;set /CE LOW, Enable movlw 0x60 ;CHIP ERASE - ENTIRE MEMORY call send_spi bcf flash_memory_status,4 ;clear START bit bsf LATD,7 ;set /CE HIGH, Disable return ;************************************************************************** run_erase bcf LATD,7 ;set /CE LOW, Enable movlw 0x05 ;read status call send_spi movlw 0x00 ;dummy data, generate clock call send_spi bsf LATD,7 ;set /CE HIGH, Disable btfsc SSP2BUF,0 ;check BUSY BIT return ;still busy... clrf flash_memory_status return ;done with erase, reset status ;******************************************************** write_status ;clears write protection bits in STATUS REGISTER bcf LATD,7 ;set /CE LOW, Enable movlw 0x06 ;WREN - write enable call send_spi bsf LATD,7 ;set /CE HIGH, Disable nop nop nop bcf LATD,7 ;set /CE LOW, Enable movlw 0x01 ;WRITE STATUS call send_spi movlw 0x00 ;DATA TO STATUS REGISTER- disable write protect bits call send_spi clrf flash_memory_status ;reset STATUS bsf LATD,7 ;set /CE HIGH, Disable return ;************************************************************************* write_mode movf write_bytes,F ;condition flags btfsc STATUS,Z return ;no bytes to write btfss flash_memory_status,4 ;test START bit bra run_write ;write remaing bytes ; call calc_flash_address ; lfsr 2,led_register ;point FSR2 at LED REGISTER bcf LATD,7 ;set /CE LOW, Enable movlw 0x70 ;enable hardware BUSY checking call send_spi bsf LATD,7 ;set /CE HIGH, Disable nop nop nop bcf LATD,7 ;set /CE LOW, Enable movlw 0x06 ;WREN - write enable call send_spi bsf LATD,7 ;set /CE HIGH, Disable nop nop nop bcf LATD,7 ;set /CE LOW, Enable movlw 0xAD ;Auto-increment word program mode enable call send_spi movlw 0 ;High address call send_spi movlw 0 ;Mid address call send_spi movlw 0 ;Low address call send_spi movf POSTINC2,W ;DATA 0 call send_spi movf POSTINC2,W ;DATA 1 call send_spi bsf LATD,7 ;set /CE HIGH, Disable nop nop nop bcf LATD,7 ;set /CE LOW, Enable- now in HARDWARE DETECT MODE bcf flash_memory_status,4 ;clear START bit decf write_bytes,F ;decrement return ;******************************************************** run_write btfss PORTD,1 ;test serial line for NOT BUSY= HI return ;it's busy, return bsf LATD,7 ;set /CE HIGH, Disable nop nop nop btfsc flash_memory_status,5 ;test WRITE END bit bra write_end ; movff flash_fsr_0,FSR2L ;RESTORE FSR pointer value ; movff flash_fsr_1,FSR2H bcf LATD,7 ;set /CE LOW, Enable movlw 0xAD ;Auto-increment word program mode enable call send_spi movf POSTINC2,W ;DATA n call send_spi movf POSTINC2,W ;DATA n+1 ;check for END OF WRITE SIGNAL btfss WREG,7 ;bit 7 of high byte is END WRITE SIGNAL bra no_end btfss WREG,6 bra no_end bsf flash_memory_status,5 ;set WRITE END bit, BOTH bits 6 AND 7 must be HIGH bcf LATC,7 ;turn OFF RED STATUS LIGHT no_end call send_spi bsf LATD,7 ;set /CE HIGH, Disable ; movff FSR2L,flash_fsr_0 ;save FSR pointer value ; movff FSR2H,flash_fsr_1 nop bcf LATD,7 ;set /CE LOW, Enable- now in HARDWARE DETECT MODE decf write_bytes,F btfss FSR2H,1 return lfsr 2,sample_buffer ;done 128 samples, reset return write_end ;shutdown write bcf LATD,7 ;set /CE LOW, Enable movlw 0x04 ;DISABLE WRITE call send_spi bsf LATD,7 ;set /CE HIGH, Disable nop nop nop bcf LATD,7 ;set /CE LOW, Enable movlw 0x80 ;DISABLE HARDWARE BUSY TEST call send_spi bsf LATD,7 ;set /CE HIGH, Disable clrf flash_memory_status ;reset system. return ;******************************************************** read_mode btfss flash_memory_status,4 ;test START bit bra run_read ;write remaing bytes bcf LATD,7 ;set /CE LOW, Enable movlw 0x03 ;enable READ call send_spi movlw 0 ;High address call send_spi movlw 0 ;Mid address call send_spi movlw 0 ;Low address call send_spi movlw 0x00 ;DUMMY DATA ;data in buffer after this! call send_spi bcf flash_memory_status,4 ;clear START bit return run_read btfss PIR3,SSP2IF ;test the interrupt flag return ;not ready movff SSP2BUF,POSTINC2 ;save byte ; movf SSP2BUF,W ;TEST GET DATA AND DO NOTHING movlw 0x00 ;DUMMY DATA ;data in buffer after this! bcf PIR3,SSP2IF ;clear the interrupt flag movwf SSP2BUF ;load data into SPI buffer, start transmission btfss FSR2L,0 incf write_bytes,F ;inc every other cycle btfss FSR2H,1 return lfsr 2,sample_buffer ;done 128 samples, reset return bsf LATD,7 ;set /CE HIGH, Disable clrf flash_memory_status ;reset return ;********************************************************* send_spi ;2 us time for this cycle bcf PIR3,SSP2IF ;clear the interrupt flag movwf SSP2BUF ;load data into SPI buffer, start transmission spi_clear_loop btfss PIR3,SSP2IF ;test the interrupt flag bra spi_clear_loop return ;done with byte ;********************************************************* erase_flash ;erase external flash video memory movlw b'00010011' ;ERASES entire chip- poll ERASE BIT or ACTIVE for done. movwf flash_memory_status call flash_loop ;service ERASE ;35 ms has elapsed return ;************************************************* flash_loop call flash_memory_routine ;service flash erase cycle movf flash_memory_status,W bnz flash_loop ;loop for external flash_erase done return ;*************************************************