; Filename: FSK_TX.SRC ; Author: Stephen Holland ; Applications Engineer ; Scenix Semiconductor Inc. ; Revision: 1.0 ; Date: July 05, 1998 ; Part: SX28AC rev. 2.5 ; Freq: 50Mhz ; Compiled using Parallax SX-Key software v0.8 ; ; *This virtual peripheral relies on an external RC filter to generate complete ; FSK signal. ; ; ; Using a PC terminal program, all data received by the UART is sent out via ; FSK transmission ; device pins28,pages4,banks8,oschs device turbo,stackx,optionx,carryx id 'FSK_TX' reset reset_entry ; ; ; Equates ; rx_pin = ra.1 tx_pin = ra.2 pwm0_pin = ra.0 ; ; ; Variables ; org 8 temp ds 1 byte ds 1 string ds 1 org 10h ;bank0 variables timers = $ ;timer timer_accl ds 1 timer_acch ds 1 timer_flag ds 1 bit_cnt ds 1 org 30h ;bank1 variables serial = $ tx_high ds 1 ;tx tx_low ds 1 tx_count ds 1 tx_divide ds 1 tx_flag ds 1 ;flag-byte ;bit 0, busy transmitting, 0=no, 1=yes tx_dly_count ds 1 rx_count ds 1 ;rx rx_divide ds 1 rx_byte ds 1 rx_flag ds 1 rx_dly_count ds 1 org 50h ;bank3 variables pwm = $ pwm_duty_1 ds 1 pwm_period_1 ds 1 lo_or_hi ds 1 counter_fsk ds 1 row ds 1 col ds 1 FSK_trm_byte ds 1 ; ; ; Interrupt routine - virtual peripherals ; org 0 interrupt ;3 it takes 3 cycles to get an interrupt bank timers ;1 ;timer stc ;1 set carry add timer_accl,#1 ;2 add timer_accl+carry(=1) sc jmp :timer_out add timer_acch,#0 snc ;1 setb timer_flag.0 ;1 :timer_out ;=7 ;********D/A CONVERSIONS************* da_conv bank pwm ;1 dec pwm_duty_1 ;1 decrement port_duty movb pwm0_pin,/pwm_duty_1.7 ;4 move complement of most significant bit to output decsz pwm_period_1 ;1 jmp da_conv_out ;3 mov pwm_duty_1,#5 ;2 jb lo_or_hi.0,:period_1200 ;1 hi for 1200, lo for 2200 :period_2200 mov pwm_period_1,#10 ;1 this is for phase coherence in freq shifts jmp :continue :period_1200 mov pwm_period_1,#9 ;2 :continue make_fsk make1200 csae counter_fsk,#end1200 ;1 take new table value jmp :continue ;1 mov counter_fsk,#sine1200 ;1 reload table-counter :continue mov w,counter_fsk ;1 mov m,#6 ;1 set page iread ;1 get table_data mov m,#$F ;1 mov pwm_duty_1,w ;1 = 21 inc counter_fsk ;1 sb lo_or_hi.0 ;1 hi for 1200, lo for 2200 inc counter_fsk ;1 this is for phase coherence in freq shifts jmp da_conv_out da_conv_out ;********SERIAL COMMUNICATIONS************* :ser_comm bank serial ;1 inc tx_dly_count ;1 inc rx_dly_count ;1 snb rx_dly_count.2 ;1 divide by 4 jmp :tst_rx ;3 sb tx_dly_count.4 ;1 = 8 ;divide by 16 jmp interrupt_out ;3 :tst_tx clr tx_dly_count ;1 jnb tx_flag.0,interrupt_out ;2 test tx_count ;1 busy? clc ;1 ready stop bit snz ;1 clrb tx_flag.0 ;1 sz ;1 if busy, shift bits rr tx_high ;1 sz ;1 rr tx_low ;1 sz ;1 ;if busy, dec counter dec tx_count ;1 movb tx_pin,/tx_low.6 ;4 =18 ;output next bit jmp interrupt_out ;3 :tst_rx clr rx_dly_count ;1 movb c,rx_pin ;4 ;serial receive test rx_count ;1 ;waiting for stop bit? jnz :rxbit ;3,2 ;if not, :bit mov w,#9 ;1 ;in case start, ready 9 bits sc ;1 ;if start, set rx_count mov rx_count,w ;1 mov rx_divide,#7 ;2 ;ready 1.5 bit periods :rxbit djnz rx_divide,:rxdone ;3,2 ;8th time through? setb rx_divide.2 ;1 ;yes, ready 1 bit period dec rx_count ;1 ;last bit? sz ;1 ;if not, save bit rr rx_byte ;1 snz ;1 ;if so, set flag setb rx_flag.1 ;1 =23 :rxdone interrupt_out mov w,#-163 ;1 ;interrupt every 159 clocks retiw ;3 ; ; ; Reset entry ; reset_entry mov ra,#%0110 ;init ra mov !ra,#%0011 ;Set ra data direction register mov m,#$F bank serial inc rx_dly_count ;just to create a slight time-shift clr fsr ;reset all ram banks :loop setb fsr.4 clr ind ijnz fsr,:loop bank pwm ;adc set speed/resolution mov pwm_period_1,#9 mov pwm_duty_1,#5 bank serial clr bit_cnt mov !option,#%10011111 ;enable rtcc interrupt ; ;************************************************************* ; Main ;************************************************************* ; ; ; Terminal - main loop ; main mov w,#_hello ;send hello string page send_string call send_string mov w,#_prompt ;send prompt string page send_string call send_string main_loop page get_byte call get_byte ; This is where the line could be tested if it clear to send, if not then jump to :send_later bank serial jnb rx_flag.7,:send_later ;If bit not set then nothing to send page FSK_send call FSK_send :send_later ; This is where a FSK_receive function would be called jmp main_loop ;************************************************************* ;************************************************************* ; Subroutines ;************************************************************* org $200 ;************************************************************* ; Jump table for page 1 ;************************************************************* FSK_send jmp FSK_send_byte FSK_send_return retp ;************************************************************* ; ; Get byte via serial port ; get_byte bank serial sb rx_flag.1 retp clrb rx_flag.1 setb rx_flag.7 ;Tell FSK module to send mov w,rx_byte ;followed by send_byte bank pwm mov FSK_trm_byte,w mov w,#_sending ;send 'sending' string page send_string call send_string bank pwm mov w,FSK_trm_byte call send_byte mov w,#_prompt ;send prompt string page send_string call send_string retp ; ; Send byte via serial port ; send_byte bank serial :wait test tx_count ;wait for not busy jnz :wait not w ;ready bits mov tx_high,w setb tx_low.7 mov tx_count,#10 ;1 start + 8 data + 1 stop bit setb tx_flag.0 retp ; ; ; Send string at w ; send_string mov string,w ;send string at w :loop mov w,string ;read chr at w mov m,#1 iread mov m,#$F test w ;if 0, exit snz retp page send_byte call send_byte ;not 0, send chr inc string ;next chr jmp :loop ; ; ; Make byte uppercase ; uppercase csae byte,#'a' ret sub byte,#'a'-'A' ret ;************************************************************* FSK_send_byte setb ra.3 ;Enable output mov !ra,#%0010 ;Enable pwm output ; This is where channel seizure or handshaking generation would be inserted. bank pwm setb lo_or_hi.0 ;Set PWM to transmit 1200Hz for start bit bank timers mov !option,#%11011111 ;disable rtcc interrupt mov timer_accl,#$5d ;1250uS mov timer_acch,#$fd ;--//-- mov !option,#%10011111 ;enable rtcc interrupt clrb timer_flag.0 ;Clear overflow-flag jnb timer_flag.0,$ ;Is overflow-flag set? mov bit_cnt,#8 ;Initialize bit_cnt :next_bit bank pwm jnb FSK_trm_byte.0,:set_2200_pwm :set_1200_pwm setb lo_or_hi.0 ;Set PWM to transmit 1200Hz jmp :set_timer_833u :set_2200_pwm clrb lo_or_hi.0 ;Set PWM to transmit 2200Hz :set_timer_833u bank timers mov !option,#%11011111 ;disable rtcc interrupt mov timer_accl,#$00 ;833uS mov timer_acch,#$fe ;--//-- mov !option,#%10011111 ;enable rtcc interrupt clrb timer_flag.0 ;Clear overflow-flag jnb timer_flag.0,$ ;Is overflow-flag set? bank pwm rr FSK_trm_byte bank timers djnz bit_cnt,:next_bit bank pwm clrb lo_or_hi.0 ;Set PWM to transmit 2200Hz for stop bit bank timers mov !option,#%11011111 ;disable rtcc interrupt mov timer_accl,#$00 ;833uS mov timer_acch,#$fe ;--//-- mov !option,#%10011111 ;enable rtcc interrupt clrb timer_flag.0 ;Clear overflow-flag jnb timer_flag.0,$ ;Is overflow-flag set? :FSK_transmit_out mov !ra,#%0011 ;Disable pwm output clrb ra.3 ;Disable output bank serial clrb rx_flag.7 jmp FSK_send_return ;************************************************************* ;************************************************************* ; org $1a0 ; ; Data ; _hello dw 13,10,13,10,'SX Modem Demo...',13,10,0 _cr dw 13,10,0 _prompt dw 13,10,'>',0 _sending dw 13,10,'Sending...',32,0 _hex dw '0123456789ABCDEF' org $600 sine1200 = $ DW 5 ; 1 DW 7 ; 2 DW 8 ; 3 DW 8 ; 4 DW 9 ; 5 DW 9 ; 6 DW 10 ; 7 DW 9 ; 8 DW 9 ; 9 DW 8 ;10 DW 8 ;11 DW 7 ;12 DW 6 ;13 DW 5 ;14 DW 3 ;15 DW 2 ;16 DW 1 ;17 DW 1 ;18 DW 0 ;19 DW 0 ;20 DW 0 ;21 DW 0 ;22 DW 0 ;23 DW 1 ;24 DW 1 ;25 DW 2 ;26 DW 3 ;27 end1200 = $ DW 4 ;28
| file: /Techref/scenix/lib/io/dev/modem/fsk.src, 9KB, , updated: 1999/2/20 11:23, local time: 2024/11/8 15:06,
3.144.250.72:LOG IN ©2024 PLEASE DON'T RIP! THIS SITE CLOSES OCT 28, 2024 SO LONG AND THANKS FOR ALL THE FISH!
|
| ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://sxlist.com/Techref/scenix/lib/io/dev/modem/fsk.src"> scenix lib io dev modem fsk</A> |
| Did you find what you needed? |
Welcome to sxlist.com!sales, advertizing, & kind contributors just like you! Please don't rip/copy (here's why Copies of the site on CD are available at minimal cost. |
Welcome to sxlist.com! |
.