dtmffsk.asm

An example to illustrate how to set the internal adjustable CID gain and receive FSK or DTMF data

;=============================================================
;An example to illustrate how to set the internal adjustable 
;CID gain and receive FSK or DTMF data. 
;Assume end-code of DTMF data string is "D".
;
;Step1. Initialize the CID system.
;Step2. Setting the CID gain control.
;Step3. Enable Ring detector (assume the FSK/DTMF signal comes 
;       between 1st and 2nd rings).
;Step4. Enable FSK and DTMF receivers when 1st ring is detected.
;Step5. Check CID interrupt resulted from FSK or DTMF receiver
;       by reading CIDFG register.
;
;If FSK interrupt then refer to step5~7.
;If DTMF interrupt then refer to step8
;--FSK---
;Step5. Confirm FSK data string by counting the number of 
;       consecutive channel seizure.
;Step6. Continuously receive FSK data string and store it in RAM 
;       till receive all data or time out.
;Step7. Verify if system receives FSK data string correctly 
;       by comparing check-sum.
;;Jump to Step10
;--DTMF---
;Step8. Read low nibble of DTMFDR to get DTMF decoded data
;Step9. Store DTMF data in RAM. 
;       Repeat step8 and step9 till end-code "D" is received or time out.
;
;Step10. Process the received data according system need.
;===============================================================

;====Define the flags for FSK receiving ======================
Flag0                   reg     23h     ;Flag register

Channel_Seizure_Flag    reg     Flag0.0  ;if the number of recognition is equal to C_Ch_Seiz_Times,set flag
FSK_Data_Flag           reg     Flag0.1  ;if FSK data string begins, set FSK_Data_Flag
FSK_Format_Flag         reg     Flag0.2  ;Set when receive FSK format data
FSK_Multiple_Format_Flag reg    Flag0.3  ;Set if the FSK format data is equal to 08h
FSK_Single_Format_Flag  reg     Flag0.4  ;Set if the FSK format data is equal to 04h
FSK_Length_Flag         reg     Flag0.5  ;Set when receive the FSK length data
FSK_Finish_Flag         reg     Flag0.6  ;Set when FSK receive data completely and correctly
;--------------------------------------------------------------
Cid_Flag1               reg     24h     ;Flag register 1      

Multiple_Length_Flag    reg     Cid_Flag1.0 ;Set when FSK receive parameter type value, clear as FSK gets parameter length
Multiple_Date_Flag      reg     Cid_Flag1.1 ;Set when FSK receive Data parameter, clear as FSK finish Date receiving
Multiple_Number_Flag    reg     Cid_Flag1.2 ;Set when FSK receive number parameter, clear as FSK finish number receiving
Multiple_Name_Flag      reg     Cid_Flag1.3 ;Set when FSK receive name parameter, Clear as finish name receiving
Multiple_Dummy_Flag     reg     Cid_Flag1.4 ;Set when FSK receiver other paramter, Clear as FSK finish dummy receiving
DTMF_Data_Flag          reg     Cid_Flag1.5 ;Set when DTMF decoder begins to receive DTMF data
CID_Finish_Flag         reg     Cid_Flag1.6 ;Set when CID receives completed data correctly
CID_Error_Flag          reg     Cid_Flag1.7 ;Set when CID (FSK) decoder recieves data incorrectly
;----------------------------------------------------------------
;====Register Definition================================ 
Cidfg_R         reg     60h     ;a register store cidfg
Counter1        reg     63h     ;normal counter
Counter2        reg     64h     ;normal counter
Data_Buffer     reg     65h     ;noram data buffer

Check_Sum       reg     66h     ;FSK check sum
Fsk_Data        reg     67h     ;a register to store FSKDR
DTMF_Data       reg     68h     ;a register to store DTMF
R0_Dp           reg     69h     ;save the data pointer of R0   
Counter_Channel_Seizure reg     6Ah     ;counter to count Channel seizure number
Data_Length     reg     6Bh     ;Store the FSK data length
Multiple_Parameter_Length       reg     6Ch     ;Store the multiple parameter length value
WDT_Counter     reg     6Dh     ;used in WDT interrupt to count the time-out times
Incall_Buf_Pointer_R1   reg     R1      ;use R1 to be the data pointer of incall structure buffer
;----------------------------------------------------------- 

;====Constant Definition===========================================
;---FSK constant-----------------------------
C_Channel_Seizure       equ     055h    ;Channel Seizure data
C_Ch_Seiz_Times         equ     03h     ;Consecutive receiving Channel seizure times
C_Single_Format         equ     04h     ;Single format code=04h
C_Multiple_Format       equ     80h     ;Multiple format code=80h

;---CID power control signal ----------
; cidprc: -  -  -  CIDE, - FSKE, CASE, DTMFE
CAS_Enable      equ     00011010b       ;enable CIDE, CASE
FSK_Enable      equ     00011100b       ;enable CIDE, FSKE
DTMF_Enable     equ     00011001b       ;enable CIDE, DTMFE
C_caspt         equ     15             ;CAS present time
C_casat         equ     24             ;CAS absent time
C_dtmfpt        equ     25             ;DTMF present time
C_dtmfat        equ     25             ;DTMF absent time

;===CID gain control registers and constants definition==================
;---The Address of Internal CID Gain Control Register---------------------
CIDGD           reg     F9h             ;CID gain control data register
CIDGA           reg     FAh             ;CID gain control address register

C_DTMFR1_Add    equ     00h             ;DTMFR1 address=00h
C_DTMFR2_Add    equ     01h             ;DTMFR2 address=01h
C_PGAF_Add      equ     02h             ;Programmable Gain control Alert tone/FSK address=02h
C_PGAD_Add      equ     03h             ;Programmable Gain control DTMF
C_PHAD_Add      equ     04h             ;Programmable Hysteresis alert tone/DTMF
C_PHFL_Add      equ     05h             ;Programmable Hysteresis FSK/Low pass filter
;---The value of programmable gain and hysteresis ----------------
C_Gain_FD       equ     09h             ;set FSK/DTMF input gain=10.05dB, PGAF<3:0>
C_Gain_A        equ     09h             ;set Alert tone input gain=10.05dB, PGAF<7:4>            
C_Gain_Row      equ     07h             ;set DTMF row(low) tone input gain=4.64dB, PGD<3:0>
C_Gain_Col      equ     0Ah             ;set DTMF column(high) tone input gain=13.53dB, PGD<7:4>
C_Hys_DTMF      equ     05h             ;set DTMF hysteresis=21mV, PHAD<3:0>
C_Hys_A         equ     03h             ;set Alert tone hysteresis=22mV, PHAD<7:4>
C_Hys_LP        equ     03h             ;set FSK Low Pass filter hysteresis=22mV, PHFL<3:0>
C_Hys_FSK       equ     03h             ;set FSK hysteresis=22mV, PHFL<7:4>  
C_dtmfr1        equ     01h             ;DTMF register1, row acceptable error freq:2.5%, 
C_dtmfr2        equ     01h             ;DTMF register2  column acceptable error freq:2.5%                            
C_Freq_Chg_Rst  equ     01h             ;1: represents DTMF PT counter will be reset by detected freq. changed
C_No_Down_Count equ     01h             ;1: DTMF AT counter is up counter only, 0:is up-down counter
;-----------------------------------------------------------------
        
        org     00h
        ljmp    Start
        org     53h                     ;The address of CID interrupt vector
        ljmp    Cid_Int

        org     70h        
Start:
        mov     sp,#0d0h                 ;stack point begins at D0H
        mov     Counter1,#00
        mov     Counter2,#00
        mov     Counter3,#00
        mov     r0,#80h                  ;for indirect data pointer from 80H
        mov     R0_Dp,r0        
  	mov	Flag0,#00h
  	mov	Cid_Flag1,#00h
        call    CID_Gain_Setting        ;Setting the internal adjustable CID gain 
        call    FSK_Flag_Initial_Setting ;Set the flags relative FSK to initial state
;---set CID control signals-------------
        mov     cidpcr,#00h              ;Off all CID power     
        mov     cidpcr,#DTMF_Enable      ;-, -, -, CIDE, -, FSKE, ASE, DTMFE
        orl     cidpcr,#Ring_Enable      ;enable ring detector        
        mov     dtmfpt,#C_dtmfpt         ;Alert Signal Present Time
        mov     dtmfat,#C_dtmfat         ;Alert Signal Absent Time        
;----clear all CID related flags--------
        mov     cidfg,#00h              ;-, -, -, -, dtmfdf,fdrf,algof,rngf
        mov     exif,#00h               ;clear exif.2=cidf, exif.3=divf
        setb    ecid                    ;enable CID interrupt(EIE.2)
        setb    ea                      ;enable global interrupt(IE.7)
;---Stay in a loop to wait for ring detection------------     
wait_ring:
	jb	CID_Finish_Flag,Correct
	jb	CID_Error_Flag,Error
	mov     a,dtmfdr                ;CASH,CASL,DTMFH,DTMFL,DD3,DD2,DD1,DD0
        jmp     wait_ring               ;User can poll DTMFH/DTMFL by reading dtmfdr register.
Correct:
        call    CID_Correct_Procedure   ;Do some procedure when data received correctly, 
        clr 	CID_Finish_Flag         ;for example, show the date, time and number on LCD 
        call    FSK_Flag_Initial_Setting ;Set the flags relative FSK to initial state
        jmp     wait_ring        
Error:
        call    CID_Error_Procedure     ;Do some procedure when data received with error
        clr     CID_Error_Flag
        call    FSK_Flag_Initial_Setting ;Set the flags relative FSK to initial state      
        jmp     wait_ring   
;============================================================================
; Caller ID interrupt
;1. Jump to Ring/CAS/FSK/DTMF interrupt according to CID flags(cidfg)
;2. Ring_Int:
;       Enable FSK receiver power
;3. FSK_Int:
;       a. Check 3 consucutive Channel_Seizure(55H) at the beginning of the FSK data string?
;          If YES: setb Channel_Seizure_Flag and Disable DTMF decoder
;          If NO:  Clear Counter_Channel_Seizure and jump to reset counter 
;                  and Check if DTMF_Int occurs?              
;       b. Check Single or Multiple format then sum up the received data:
;          The first byte of FSK data string is either 04H(Single) or 80H(Multiple).
;       c. Continueously store and sum up received data till the number of received bytes
;          is equal to the FSK length data.
;       d. Compare the check sum:
;          If Correct: setb CID_Finish_Flag
;          If Error:   setb CID_Error_Flag
;4.DTMF_Int:
;       a. Store the low nibble of DTMFDR into DTMF_Data
;       b. Check Start or End code.
;============================================================================
Cid_Int:
        mov     Cidfg_R,cidfg           ;record CIDFG register