; ***************************************************************************************** ; Copyright © [01/26/1999] Scenix Semiconductor, Inc. All rights reserved. ; ; Scenix Semiconductor, Inc. assumes no responsibility or liability for ; the use of this [product, application, software, any of these products]. ; Scenix Semiconductor conveys no license, implicitly or otherwise, under ; any intellectual property rights. ; Information contained in this publication regarding (e.g.: application, ; implementation) and the like is intended through suggestion only and may ; be superseded by updates. Scenix Semiconductor makes no representation ; or warranties with respect to the accuracy or use of these information, ; or infringement of patents arising from such use or otherwise. ;***************************************************************************************** ; ; Filename: simple_fsk_rcv_1_10.src ; ; Authors: Chris Fogelklou ; Applications Engineer ; Scenix, Inc. ; ; Revision: 1.10 ; ; Part: SX28AC datecode 9929AA ; ; Freq: 50Mhz ; ; Compiled using Parallax SX-Key software v1.07 and SASM 1.40 ; ; Date Written: January 25, 1999 ; ; Last Revised: November 17, 1999 ; ; Program Description: This is simple software to demonstrate the concept of ; converting an incoming frequency to a data train. This ; program simply watches the incoming frequency and outputs ; a high or a low to the RS-232 TX pin. For this reason, the ; PC that the board is connected to must be set to the desired ; baud rate. Example: If a 300,N,8,1 settings are desired, ; simply set the PC's terminal program to these settings and ; the SX modem will act as a simple frequency-voltage converter, ; translating the incoming frequency (1300Hz and 2100Hz) to ; an output voltage which the computer will receive as a 300,N,8,1 ; data packet. Once the modem is connected, simply press a key ; on the keyboard to get it to pick up and begin receiving. ; ; Disclaimer: This program is simplified... It is just ; for demo purposes, to show the power and ; simplicity of Virtual Peripherals for telephony ; applications. An actual modem would need a ; more complex algorithm (See the V.23 Modem Appnote) ; to achieve sufficient error response. ; ; Note: This program works only with an accurate Oscillator. ; The SX-ISD's Oscillator is not accurate enough to ; produce error-free results. The XTAL on the Scenix ; Demo boards produced better results. ; ; INPUTS: ; FSK input on fsk_rx_pin (rb.1) (Signal must be passed through comparator/zero-cross ; circuitry.) ; RS-232 input on rx_pin (ra.1) ; ; OUTPUTS: ; Received RS-232 characters on tx_pin (ra.2) ; LED flashes while receiving on led_pin (rb.0) ; ; Revision History: 1.0 Drew out the FSK receive code from the rest of the code ; surrounding it in the old modem demo software and implemented ; it as a module by itself (December 17, 1998) ; 1.01 Added more documentation to the software for web-posting. ; (January 25, 1999) ; 1.02 Added support for rev 1.4 boards (2/23/99) ; 1.10 Updated the program for the SASM assembler ; ; RESOURCES: ; Program memory: 91 Words ; Data memory: 2 1/8 bytes ;***************************************************************************************** ;***************************************************************************************** ; Target SX ; Uncomment one of the following lines to choose the SX18AC, SX20AC, SX28AC, SX48BD/ES, ; SX48BD, SX52BD/ES or SX52BD. For SX48BD/ES and SX52BD/ES, uncomment both defines, ; SX48_52 and SX48_52_ES. ;***************************************************************************************** ;SX18_20 SX28 ;SX48_52 ;SX48_52_ES ;***************************************************************************************** ; Assembler Used ; Uncomment the following line if using the Parallax SX-Key assembler. SASM assembler ; enabled by default. ;***************************************************************************************** SX_Key ;********************************************************************************* ; Assembler directives: ; high speed external osc, turbo mode, 8-level stack, and extended option reg. ; ; SX18/20/28 - 4 pages of program memory and 8 banks of RAM enabled by default. ; SX48/52 - 8 pages of program memory and 16 banks of RAM enabled by default. ; ;********************************************************************************* IFDEF SX_Key ;SX-Key Directives IFDEF SX18_20 ;SX18AC or SX20AC device directives for SX-Key device SX18L,oschs2,turbo,stackx_optionx ENDIF IFDEF SX28 ;SX28AC device directives for SX-Key device SX28L,oschs2,turbo,stackx_optionx ENDIF IFDEF SX48_52_ES ;SX48BD/ES or SX52BD/ES device directives for SX-Key device oschs,turbo,stackx,optionx ELSE IFDEF SX48_52 ;SX48/52/BD device directives for SX-Key device oschs2 ENDIF ENDIF freq 50_000_000 ELSE ;SASM Directives IFDEF SX18_20 ;SX18AC or SX20AC device directives for SASM device SX18,oschs2,turbo,stackx,optionx ENDIF IFDEF SX28 ;SX28AC device directives for SASM device SX28,oschs2,turbo,stackx,optionx ENDIF IFDEF SX48_52_ES ;SX48BD/ES or SX52BD/ES device directives for SASM device SX52,oschs,turbo,stackx,optionx ELSE IFDEF SX48_52 ;SX48BD or SX52BD device directives for SASM device SX52,oschs2 ENDIF ENDIF ENDIF id 'SFSKRX11' ; reset reset_entry ; set reset vector ;***************************************************************************************** ; Macros ;***************************************************************************************** ;********************************************************************************* ; Macro: _bank ; Sets the bank appropriately for all revisions of SX. ; ; This is required since the bank instruction has only a 3-bit operand, it cannot ; be used to access all 16 banks of the SX48/52. For this reason FSR.4 (for SX48/52BD/ES) ; or FSR.7 (SX48/52bd production release) needs to be set appropriately, depending ; on the bank address being accessed. This macro fixes this. ; ; So, instead of using the bank instruction to switch between banks, use _bank instead. ; ;********************************************************************************* _bank macro 1 bank \1 IFDEF SX48_52 IFDEF SX48_52_ES IF \1 & %00010000 ;SX48BD/ES and SX52BD/ES (engineering sample) bank instruction setb fsr.4 ;modifies FSR bits 5,6 and 7. FSR.4 needs to be set by software. ENDIF ELSE IF \1 & %10000000 ;SX48BD and SX52BD (production release) bank instruction setb fsr.7 ;modifies FSR bits 4,5 and 6. FSR.7 needs to be set by software. ELSE clrb fsr.7 ENDIF ENDIF ENDIF endm ;********************************************************************************* ; Macro: _mode ; Sets the MODE register appropriately for all revisions of SX. ; ; This is required since the MODE (or MOV M,#) instruction has only a 4-bit operand. ; The SX18/20/28AC use only 4 bits of the MODE register, however the SX48/52BD have ; the added ability of reading or writing some of the MODE registers, and therefore use ; 5-bits of the MODE register. The MOV M,W instruction modifies all 8-bits of the ; MODE register, so this instruction must be used on the SX48/52BD to make sure the MODE ; register is written with the correct value. This macro fixes this. ; ; So, instead of using the MODE or MOV M,# instructions to load the M register, use ; _mode instead. ; ;********************************************************************************* _mode macro 1 IFDEF SX48_52 mov w,#\1 ;loads the M register correctly for the SX48BD and SX52BD mov m,w ELSE mov m,#\1 ;loads the M register correctly for the SX18AC, SX20AC ;and SX28AC ENDIF endm ;***************************************************************************************** ; Data Memory address definitions ; These definitions ensure the proper address is used for banks 0 - 7 for 2K SX devices ; (SX18/20/28) and 4K SX devices (SX48/52). ;***************************************************************************************** IFDEF SX48_52 global_org = $0A bank0_org = $00 bank1_org = $10 bank2_org = $20 bank3_org = $30 bank4_org = $40 bank5_org = $50 bank6_org = $60 bank7_org = $70 ELSE global_org = $08 bank0_org = $10 bank1_org = $30 bank2_org = $50 bank3_org = $70 bank4_org = $90 bank5_org = $B0 bank6_org = $D0 bank7_org = $F0 ENDIF ;***************************************************************************************** ; Global Register definitions ; NOTE: Global data memory starts at $0A on SX48/52 and $08 on SX18/20/28. ;***************************************************************************************** org global_org function_temp equ global_org+1 global_temp equ global_org+2 ;***************************************************************************************** ; RAM Bank Register definitions ;***************************************************************************************** ;********************************************************************************* ; Bank 0 ;********************************************************************************* org bank0_org bank0 = $ flags ds 1 fsk_rx_en equ flags.0 ; Enables the FSK receiver. ;********************************************************************************* ; Bank 1 ;********************************************************************************* org bank1_org bank1 = $ fsk_receive_bank = $ fsk_trans_count ds 1 ; This register counts the number of counts ; between transitions at the pin rb_past_state ds 1 ; This register keeps track of the previous ; state of port RB, to watch for transitions ;********************************************************************************* ; Bank 2 ;********************************************************************************* org bank2_org bank2 = $ ;********************************************************************************* ; Bank 3 ;********************************************************************************* org bank3_org bank3 = $ ;********************************************************************************* ; Bank 4 ;********************************************************************************* org bank4_org bank4 = $ ;********************************************************************************* ; Bank 5 ;********************************************************************************* org bank5_org bank5 = $ ;********************************************************************************* ; Bank 6 ;********************************************************************************* org bank6_org bank6 = $ ;********************************************************************************* ; Bank 7 ;********************************************************************************* org bank7_org bank7 = $ IFDEF SX48_52 ;********************************************************************************* ; Bank 8 ;********************************************************************************* org $80 ;bank 8 address on SX52 bank8 = $ ;********************************************************************************* ; Bank 9 ;********************************************************************************* org $90 ;bank 9 address on SX52 bank9 = $ ;********************************************************************************* ; Bank A ;********************************************************************************* org $A0 ;bank A address on SX52 bankA = $ ;********************************************************************************* ; Bank B ;********************************************************************************* org $B0 ;bank B address on SX52 bankB = $ ;********************************************************************************* ; Bank C ;********************************************************************************* org $C0 ;bank C address on SX52 bankC = $ ;********************************************************************************* ; Bank D ;********************************************************************************* org $D0 ;bank D address on SX52 bankD = $ ;********************************************************************************* ; Bank E ;********************************************************************************* org $E0 ;bank E address on SX52 bankE = $ ;********************************************************************************* ; Bank F ;********************************************************************************* org $F0 ;bank F address on SX52 bankF = $ ENDIF ;********************************************************************************* ; Pin Definitions (These pins are for use with the Scenix Modem Demo Board, ; Rev. 1.2) ;********************************************************************************* PDM_pin equ ra.0 ; D/A output pin rx_pin equ ra.1 ; RS-232 reception pin tx_pin equ ra.2 ; RS-232 transmission pin nothing equ ra.3 ; N/C RA_latch equ %11111111 ;SX18/20/28/48/52 port A latch init RA_DDIR equ %11111011 ;SX18/20/28/48/52 port A DDIR value RA_LVL equ %00000000 ;SX18/20/28/48/52 port A LVL value RA_PLP equ %11111111 ;SX18/20/28/48/52 port A PLP value led_pin equ rb.0 ; LED pin rxa_pin equ rb.1 ; FSK receive pin cntrl_1 equ rb.2 ; drive cntrl_1 low to disable the output of the LPF ring equ rb.3 ; ring detection pin hook equ rb.4 ; drive hook low to go off-hook cntrl_3 equ rb.5 ; drive cntrl_3 low to disable the output of the HPF rts equ rb.6 ; indicates to the SX that the PC wants to transmit data cts equ rb.7 ; indicates to the PC that the SX is ready to receive data RB_latch equ %11011011 ;SX18/20/28/48/52 port B latch init RB_DDIR equ %01101010 ;SX18/20/28/48/52 port B DDIR value RB_ST equ %11111111 ;SX18/20/28/48/52 port B ST value RB_LVL equ %00000000 ;SX18/20/28/48/52 port B LVL value RB_PLP equ %11111111 ;SX18/20/28/48/52 port B PLP value dtmf_in_pin equ rc.0 ; DTMF input pin dtmf_fdbk_pin equ rc.1 ; Negative feedback output for DTMF input AtoD_in_pin equ rc.2 ; A/D input pin AtoD_fdbk_pin equ rc.3 ; Negative feedback for A/D input imp_450_pin equ rc.4 ; Set to an output to set hybrid for 450ohm line impedance. Tristate otherwise. imp_600_pin equ rc.5 ; Set to an output to set hybrid for 600ohm line impedance. Tristate otherwise. imp_750_pin equ rc.6 ; Set to an output to set hybrid for 750ohm line impedance. Tristate otherwise. imp_900_pin equ rc.7 ; Set to an output to set hybrid for 900ohm line impedance. Tristate otherwise. RC_latch equ %00001111 ;SX18/20/28/48/52 port C latch init RC_DDIR equ %11010101 ;SX18/20/28/48/52 port C DDIR value RC_ST equ %11111111 ;SX18/20/28/48/52 port C ST value RC_LVL equ %00000000 ;SX18/20/28/48/52 port C LVL value RC_PLP equ %11111111 ;SX18/20/28/48/52 port C PLP value IFDEF SX48_52 ;SX48BD/52BD Port initialization values RD_latch equ %00000000 ;SX48/52 port D latch init RD_DDIR equ %11111111 ;SX48/52 port D DDIR value RD_ST equ %11111111 ;SX48/52 port D ST value RD_LVL equ %00000000 ;SX48/52 port D LVL value RD_PLP equ %11111111 ;SX48/52 port D PLP value RE_latch equ %00000000 ;SX48/52 port E latch init RE_DDIR equ %11111111 ;SX48/52 port E DDIR value RE_ST equ %11111111 ;SX48/52 port E ST value RE_LVL equ %00000000 ;SX48/52 port E LVL value RE_PLP equ %11111111 ;SX48/52 port E PLP value ENDIF ;***************************************************************************************** ; Program constants ;***************************************************************************************** ;****************************************************************************** ; Equates for FSK reception ;****************************************************************************** glitch_th equ 20 ; The threshold which defines a glitch (small spike which should be ignored) low_count_error_th equ 40 ; The lowest count allowed for a high frequency low_high_th equ 95 ; The lowest count allowed for a low frequency high_count_error_th equ 140 ; The highest count allowed for a low frequency int_period equ 163 ;RTCC Interrupt rate IFDEF SX48_52 ;********************************************************************************* ; SX48BD/52BD Mode addresses ; *On SX48BD/52BD, most registers addressed via mode are read and write, with the ; exception of CMP and WKPND which do an exchange with W. ;********************************************************************************* ; Timer (read) addresses TCPL_R equ $02 ;Read Timer Capture register low byte TCPH_R equ $02 ;Read Timer Capture register high byte TR2CML_R equ $02 ;Read Timer R2 low byte TR2CMH_R equ $03 ;Read Timer R2 high byte TR1CML_R equ $04 ;Read Timer R1 low byte TR1CMH_R equ $05 ;Read Timer R1 high byte TCNTB_R equ $06 ;Read Timer control register B TCNTA_R equ $07 ;Read Timer control register A ; Exchange addresses CMP equ $08 ;Exchange Comparator enable/status register with W WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W ; Port setup (read) addresses WKED_R equ $0A ;Read MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising WKEN_R equ $0B ;Read MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled ST_R equ $0C ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled LVL_R equ $0D ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled PLP_R equ $0E ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled DDIR_R equ $0F ;Read Port Direction ; Timer (write) addresses TR2CML_W equ $12 ;Write Timer R2 low byte TR2CMH_W equ $13 ;Write Timer R2 high byte TR1CML_W equ $14 ;Write Timer R1 low byte TR1CMH_W equ $15 ;Write Timer R1 high byte TCNTB_W equ $16 ;Write Timer control register B TCNTA_W equ $17 ;Write Timer control register A ; Port setup (write) addresses WKED_W equ $1A ;Write MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising WKEN_W equ $1B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled ST_W equ $1C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled LVL_W equ $1D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled PLP_W equ $1E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled DDIR_W equ $1F ;Write Port Direction ELSE ;********************************************************************************* ; SX18AC/20AC/28AC Mode addresses ; *On SX18/20/28, all registers addressed via mode are write only, with the exception of ; CMP and WKPND which do an exchange with W. ;********************************************************************************* ; Exchange addresses CMP equ $08 ;Exchange Comparator enable/status register with W WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W ; Port setup (read) addresses WKED_W equ $0A ;Write MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising WKEN_W equ $0B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled ST_W equ $0C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled LVL_W equ $0D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled PLP_W equ $0E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled DDIR_W equ $0F ;Write Port Direction ENDIF ;***************************************************************************************** ; Interrupt Service Routine ;***************************************************************************************** ; Note: The interrupt code must always originate at address $0. ; ; Interrupt Frequency = (Cycle Frequency / -(retiw value)) For example: ; With a retiw value of -163 and an oscillator frequency of 50MHz, this ; code runs every 3.26us. ;***************************************************************************************** org $0 interrupt ;3 ;********************************************************************************* ; Virtual Peripheral: FSK Detection (Simple) ; ; ; Input variable(s): fsk_rx_en: Enables/Disables this routine ; RB.1: FSK Input on this port pin. ; Output variable(s): Sets/Clears the LED_pin and the tx_pin, depending on ; the current input frequency ; Variable(s) affected: fsk_trans_count, rb_past_state ; Flag(s) affected: None ; Variable Length?: Yes. ;********************************************************************************* jnb fsk_rx_en,fsk_rx_out ; jump out if the FSK receiver is not enabled FSK_RECEIVE bank fsk_receive_bank ; switch to fsk_receive_bank of RAM add fsk_trans_count,#1 ; Regardless of what is going on, increment the snc ; transition timer. These get cleared when a transition jmp :error ; takes place. cjb fsk_trans_count,#low_high_th,:fsk_timer_out ; as soon as it takes longer than 95 counts setb tx_pin ; to transition, this must be a low frequency clrb LED_pin ; If a high is being sent, clear the LED :fsk_timer_out mov w,rb and w,#%00000010 ; get the current state of rb. xor w,rb_past_state ; compare it with the previous state of the pin jz fsk_rx_out ; if there was no change, then jump out, there is nothing to do. ; Now it is time to determine if the transition that took place indicates a bit was received ; (it must be within some thresholds... below 20, ignore it, below 40, what???, ; below 95, high frequency, below 140, low frequency (already set), above 140, ; what???) cjb fsk_trans_count,#glitch_th,:glitch_so_ignore ; pulse was below specs, ignore it... probably noise cjb fsk_trans_count,#low_count_error_th,:error ; pulse was not a glitch but wasn't long enough to mean anything... huh? cjb fsk_trans_count,#low_high_th,:high_frequency ; pulse was within specs for a high frequency... cjb fsk_trans_count,#high_count_error_th,:fsk_receive_done ; pulse was within specs for a low frequency (don't do anything) jmp :error ; pulse was too long to mean anything, so do nothing. :high_frequency ; a high frequency corresponds to low data. clrb tx_pin setb LED_pin ; set the LED to indicate a LOW is being sent. jmp :fsk_receive_done :error ;--------------- PUT ERROR HANDLING CODE IN HERE ----------------- :fsk_receive_done clr fsk_trans_count ; clear the bit counter. :glitch_so_ignore ; don't clear the counter if the data was a glitch mov w,rb ; save the new state of RB. and w,#%00000010 mov rb_past_state,w fsk_rx_out ;********************************************************************************* ; Set Interrupt Rate ;********************************************************************************* isr_end mov w,#-int_period ;refresh RTCC on return retiw ;return from the interrupt ; = 1/(int_period*RTCC prescaler*1/50MHz) ; = 1/(163*1*20ns) = 1/3.26us = 306.7kHz ;***************************************************************************************** ; End of the Interrupt Service Routine ;***************************************************************************************** ;***************************************************************************************** ; RESET VECTOR ;***************************************************************************************** ;********************************************************************************* ; Program execution begins here on power-up or after a reset ;********************************************************************************* reset_entry jmp @_reset_entry ; Go to the location in the last page where the ; main program is. ;***************************************************************************************** org $200 ;***************************************************************************************** ; Jump table for page 1 ; Enables CALLs to functions in the second half of the page ;***************************************************************************************** ;function_label_2 jmp function_label_2_ ;***************************************************************************************** ; Subroutines ;***************************************************************************************** ;********************************************************************************* ; Function: ; ; Inputs: ; ; Outputs: ; ; Registers affected: ; ; Functions Called: ; ;********************************************************************************* ;function_label ; retp ;********************************************************************************* ; Function: ; ; Inputs: ; ; Outputs: ; ; Registers affected: ; ; Functions Called: ; ;********************************************************************************* ;function_label_1 ; retp ;********************************************************************************* ; Function: ; ; Inputs: ; ; Outputs: ; ; Registers affected: ; ; Functions Called: ; ;********************************************************************************* ;function_label_2_ ; retp ;***************************************************************************************** org $400 ;***************************************************************************************** ;***************************************************************************************** org $600 ;***************************************************************************************** ;***************************************************************************************** ; RESET VECTOR ;***************************************************************************************** ;********************************************************************************* ; Program execution begins here on power-up or after a reset ;********************************************************************************* _reset_entry ;********************************************************************************* ; Initialise all port configuration ;********************************************************************************* _mode ST_W ;point MODE to write ST register mov w,#RB_ST ;Setup RB Schmitt Trigger, 0 = enabled, 1 = disabled mov !rb,w mov w,#RC_ST ;Setup RC Schmitt Trigger, 0 = enabled, 1 = disabled mov !rc,w IFDEF SX48_52 mov w,#RD_ST ;Setup RD Schmitt Trigger, 0 = enabled, 1 = disabled mov !rd,w mov w,#RE_ST ;Setup RE Schmitt Trigger, 0 = enabled, 1 = disabled mov !re,w ENDIF _mode LVL_W ;point MODE to write LVL register mov w,#RA_LVL ;Setup RA CMOS or TTL levels, 0 = TTL, 1 = CMOS mov !ra,w mov w,#RB_LVL ;Setup RB CMOS or TTL levels, 0 = TTL, 1 = CMOS mov !rb,w mov w,#RC_LVL ;Setup RC CMOS or TTL levels, 0 = TTL, 1 = CMOS mov !rc,w IFDEF SX48_52 mov w,#RD_LVL ;Setup RD CMOS or TTL levels, 0 = TTL, 1 = CMOS mov !rd,w mov w,#RE_LVL ;Setup RE CMOS or TTL levels, 0 = TTL, 1 = CMOS mov !re,w ENDIF _mode PLP_W ;point MODE to write PLP register mov w,#RA_PLP ;Setup RA Weak Pull-up, 0 = enabled, 1 = disabled mov !ra,w mov w,#RB_PLP ;Setup RB Weak Pull-up, 0 = enabled, 1 = disabled mov !rb,w mov w,#RC_PLP ;Setup RC Weak Pull-up, 0 = enabled, 1 = disabled mov !rc,w IFDEF SX48_52 mov w,#RD_PLP ;Setup RD Weak Pull-up, 0 = enabled, 1 = disabled mov !rd,w mov w,#RE_PLP ;Setup RE Weak Pull-up, 0 = enabled, 1 = disabled mov !re,w ENDIF _mode DDIR_W ;point MODE to write DDIR register mov w,#RA_DDIR ;Setup RA Direction register, 0 = output, 1 = input mov !ra,w mov w,#RB_DDIR ;Setup RB Direction register, 0 = output, 1 = input mov !rb,w mov w,#RC_DDIR ;Setup RC Direction register, 0 = output, 1 = input mov !rc,w IFDEF SX48_52 mov w,#RD_DDIR ;Setup RD Direction register, 0 = output, 1 = input mov !rd,w mov w,#RE_DDIR ;Setup RE Direction register, 0 = output, 1 = input mov !re,w ENDIF mov w,#RA_latch ;Initialize RA data latch mov ra,w mov w,#RB_latch ;Initialize RB data latch mov rb,w mov w,#RC_latch ;Initialize RC data latch mov rc,w IFDEF SX48_52 mov w,#RD_latch ;Initialize RD data latch mov rd,w mov w,#RE_latch ;Initialize RE data latch mov re,w ENDIF ;********************************************************************************* ; Clear all Data RAM locations ;********************************************************************************* IFDEF SX48_52 ;SX48/52 RAM clear routine mov w,#$0a ;reset all ram starting at $0A mov fsr,w :zero_ram clr ind ;clear using indirect addressing incsz fsr ;repeat until done jmp :zero_ram _bank bank0 ;clear bank 0 registers clr $10 clr $11 clr $12 clr $13 clr $14 clr $15 clr $16 clr $17 clr $18 clr $19 clr $1a clr $1b clr $1c clr $1d clr $1e clr $1f ELSE ;SX18/20/28 RAM clear routine clr fsr ;reset all ram banks :zero_ram sb fsr.4 ;are we on low half of bank? setb fsr.3 ;If so, don't touch regs 0-7 clr ind ;clear using indirect addressing incsz fsr ;repeat until done jmp :zero_ram ENDIF ;********************************************************************************* ; Initialize program/VP registers ;********************************************************************************* ;********************************************************************************* ; Setup and enable RTCC interrupt, WREG register, RTCC/WDT prescaler ;********************************************************************************* RTCC_ON = %10000000 ;Enables RTCC at address $01 (RTW hi) ;*WREG at address $01 (RTW lo) by default RTCC_ID = %01000000 ;Disables RTCC edge interrupt (RTE_IE hi) ;*RTCC edge interrupt (RTE_IE lo) enabled by default RTCC_INC_EXT = %00100000 ;Sets RTCC increment on RTCC pin transition (RTS hi) ;*RTCC increment on internal instruction (RTS lo) is default RTCC_FE = %00010000 ;Sets RTCC to increment on falling edge (RTE_ES hi) ;*RTCC to increment on rising edge (RTE_ES lo) is default RTCC_PS_ON = %00000000 ;Assigns prescaler to RTCC (PSA lo) RTCC_PS_OFF = %00001000 ;Assigns prescaler to RTCC (PSA lo) PS_000 = %00000000 ;RTCC = 1:2, WDT = 1:1 PS_001 = %00000001 ;RTCC = 1:4, WDT = 1:2 PS_010 = %00000010 ;RTCC = 1:8, WDT = 1:4 PS_011 = %00000011 ;RTCC = 1:16, WDT = 1:8 PS_100 = %00000100 ;RTCC = 1:32, WDT = 1:16 PS_101 = %00000101 ;RTCC = 1:64, WDT = 1:32 PS_110 = %00000110 ;RTCC = 1:128, WDT = 1:64 PS_111 = %00000111 ;RTCC = 1:256, WDT = 1:128 mov w,#RTCC_PS_OFF ;setup option register mov !option,w jmp @main ;***************************************************************************************** ; MAIN PROGRAM CODE ;***************************************************************************************** ;********************************************************************************* ; Main ;********************************************************************************* main clrb CTS jb rx_pin,$ ; until the user presses a key, loop indefinetely clrb hook ; pick up the line setb fsk_rx_en ; enable the FSK receiver ;********************************************************************************* ; Main Program Loop ;********************************************************************************* main_loop ; Do nothing... ISR Does everything. jmp main_loop ;***************************************************************************************** END ;End of program code ;*****************************************************************************************
file: /Techref/scenix/lib/io/dev/modem/simple_fsk_rcv_1_10.SRC, 32KB, , updated: 2002/4/11 13:05, local time: 2024/8/14 22:41,
3.131.38.22:LOG IN
|
©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/simple_fsk_rcv_1_10.SRC"> scenix lib io dev modem simple_fsk_rcv_1_10</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. |
Ashley Roll has put together a really nice little unit here. Leave off the MAX232 and keep these handy for the few times you need true RS232! |
.