; ******************************************************************* ; This program reads a character from the PC serial interface, and ; uses a lookup table to decide which tone to generate. It then ; synthesises a DTMF tone for a fixed period of time, then zeros the ; ouput of the DAC. ; Note that with a 40MHz CPU clock, the actual sampling frequency could ; not be set to exactly 8kHz. It was defined to be 7936.5Hz, and the ; values in the key_table reflect this alteration. ; Note that flags are used to determine when to process new data. ; If the flag is set to 00FFh then an interrupt has occured, and the ; program branches to the relevant service routine. ; When a transmit interrupt occurs the program branches to the transmit ; interrupt service routine and sets the tx_flag. It then gets data ; from data ram and writes it to the tx serial port register. ; Written by Steven J. Merrifield, 1994 ; ******************************************************************* .sect "VECTORS" b start ; 0 - External reset b INT0 ; 2 - User int 0 b INT1 ; 4 - User int 1 b INT2 ; 6 - User int 2 b d_int ; 8 - Reserved b d_int ; 10 - Reserved b d_int ; 12 - Reserved b d_int ; 14 - Reserved b d_int ; 16 - Reserved b d_int ; 18 - Reserved b d_int ; 20 - Reserved b d_int ; 22 - Reserved b tim_int ; 24 - Internal timer b rx_int ; 26 - Serial port rx b tx_int ; 28 - Serial port tx b d_int ; 30 - Trap instruction addr. .text sine .word 0000h, 0324h, 0646h, 0964h, 0c7ch, 0f8dh, 1294h .word 1590h, 187eh, 1b5dh, 1e2bh, 20e7h, 238eh, 2620h .word 289ah, 2afbh, 2d41h, 2f6ch, 3179h, 3368h, 3537h .word 36e5h, 3871h, 39dbh, 3b21h, 3c42h, 3d3fh, 3e15h .word 3ec5h, 3f4fh, 3fb1h, 3fech, 4000h, 3fech, 3fb1h .word 3f4fh, 3ec5h, 3e15h, 3d3fh, 3c42h, 3b21h, 39dbh .word 3871h, 36e5h, 3537h, 3368h, 3179h, 2f6ch, 2d41h .word 2afbh, 289ah, 2620h, 238eh, 20e7h, 1e2bh, 1b5dh .word 187eh, 1590h, 1294h, 0f8dh, 0c7ch, 0964h, 0646h .word 0324h, 0000h .word 0fcdch, 0f9bah, 0f9bah, 0f69ch, 0f384h, 0f073h .word 0ed6ch, 0ea70h, 0e782h, 0e4a3h, 0e1d5h, 0df19h .word 0dc72h, 0d9e0h, 0d766h, 0d505h, 0d2bfh, 0d094h .word 0ce87h, 0cc98h, 0cac9h, 0c91bh, 0c78fh, 0c625h .word 0c4dfh, 0c3beh, 0c2c1h, 0c1ebh, 0c13bh, 0c0b1h .word 0c04fh, 0c014h, 0c000h, 0c014h, 0c04fh, 0c0b1h .word 0c13bh, 0c1ebh, 0c2c1h, 0c3beh, 0c4dfh, 0c625h .word 0c78fh, 0c91bh, 0cac9h, 0cc98h, 0ce87h, 0d094h .word 0d2bfh, 0d505h, 0d766h, 0d9e0h, 0dc72h, 0df19h .word 0e1d5h, 0e4a3h, 0e782h, 0ea70h, 0ed6ch, 0f073h .word 0f384h, 0f69ch, 0f9bah, 0fcdch m1 .word 07fffh key_table .word 0f2dh, 158ch ; 0 .word 0b3dh, 137fh ; 1 .word 0b3dh, 158ch ; 2 .word 0b3dh, 17d2h ; 3 .word 0c6bh, 137fh ; 4 .word 0c6bh, 158ch ; 5 .word 0c6bh, 17d2h ; 6 .word 0dbdh, 137fh ; 7 .word 0dbdh, 158ch ; 8 .word 0dbdh, 17d2h ; 9 .word 0b3dh, 1a56h ; A .word 0c6bh, 1a56h ; B .word 0dbdh, 1a56h ; C .word 0f2dh, 1a56h ; D .word 0f2dh, 137fh ; * .word 0f2dh, 17d2h ; # ; IO ports u_data .set 4 u_ctrl .set 5 ; Page 0 variables (0000h) dxr .set 1 ; data tx reg. address imr .set 4 ; interrupt mask reg. tx_flag .set 96 ; data has been sent flag stat_st .set 97 ; temp for saving status reg accl_st .set 98 ; temp for low half of accumulator acch_st .set 99 ; temp for high half of accumulator tx_data .set 100 ; data to be tx'ed must be stored here init_data .set 101 ; data for init. must be stored here init_flag .set 102 ; flag for secondary communications delta1 .set 107 ; increment for first sine wave alpha1 .set 108 sin1 .set 109 ; actual sine wave value temp .set 110 mask .set 111 sin_offset .set 112 ; pointer into sine lookup table key_offset .set 113 ; pointer into keypad lookup table temp2 .set 114 temp3 .set 115 tone_len .set 116 ; address for time one tone is sent delta2 .set 117 ; increment for second sine wave alpha2 .set 118 sin2 .set 119 ; actual sine wave value last .set 120 sec_last .set 121 ; ******************************************************************* ; Initialization ; ******************************************************************* start ldpk 0 ; point to data page zero fort 0 ; set serial port to be 16 bits wide rtxm ; external sync sfsm ; sync required for each transfer cnfd ; configure block B0 as data zac ; reset tx and init flags sacl tx_flag sacl init_flag larp ar1 ; counter for time one tone is sent eint lalk 020h ; enable only tx interrupt sacl imr ; ******************************************************************* ; Main program ; ******************************************************************* lalk 1223h ; setup TA and RA (divide by 9) sacl init_data call tx_ready lalk 1 sacl init_flag wait_2nd_a lac init_flag ; wait until secondary comms is finished bnz wait_2nd_a lalk 468eh ; setup TB and RB (divide by 35) sacl init_data call tx_ready lalk 1 sacl init_flag wait_2nd_b lac init_flag ; wait until secondary comms is finished bnz wait_2nd_b lalk 1000 ; time one time is transmitted (50ms) sacl tone_len lalk m1 tblr mask lalk sine ; save start addr. of sinewave lookup table sacl sin_offset zac sacl alpha1 ; start at zero in sine LUT sacl alpha2 sacl delta1 sacl delta2 lalk key_table ; prepare keypad lookup table sacl key_offset loop call check_key ; see if a key has been pressed lac alpha1,8 sach temp lac temp add sin_offset tblr sin1 ; calculate first sine wave sample lac alpha1 add delta1 and mask sacl alpha1 ; 2nd sine wave lac alpha2,8 sach temp lac temp add sin_offset tblr sin2 ; calculate second sine wave sample lac alpha2 add delta2 and mask sacl alpha2 lac sin1 ; add the first and second together add sin2 sacl tx_data ; write the combined sum to DAC call tx_ready banz loop ; banz has got a built in decrement zac ; when loop has run down, zero DAC output sacl alpha1 sacl alpha2 sacl delta1 sacl delta2 b loop ; ******************************************************************* ; Check if a key was pressed ; ******************************************************************* check_key in temp2,u_ctrl ; test if key pressed bit temp2,14 bbz end_check in temp2,u_data ; read data from uart into temp addr. lac temp2 ; remove top half since IN only reads andk 00FFh ; an 8 bit number, so the top 8 bits sacl temp2 ; will be garbage! lac temp2,1 ; mult kbhit by 2 since LUT uses row-col add key_offset ; move to correct position in LUT tblr delta1 ; read row value from LUT addk 1 tblr delta2 ; read column value from LUT lar ar1, tone_len ; reset tone length after every keypress end_check ret ; ******************************************************************* ; Test if transmit flag is set ; ******************************************************************* tx_ready lac tx_flag ; when flag is set, tx_flag = 0ffh andk 00ffh subk 0ffh bnz tx_ready ; wait until flag is set sacl tx_flag ; if flag is set, then reset it ret ; ******************************************************************* ; Transmit interrupt service routine ; ******************************************************************* tx_int sst stat_st ; push status reg sacl accl_st ; push accumulator sach acch_st bit init_flag,14 ; are we sending init. data? bbz test_2nd send_2nd lac init_data ; send actual init. data (ie divide no's) sacl dxr zac sacl init_flag ; reset init flag b exit_tx_int test_2nd bit init_flag,15 bbnz send_1st primary lalk 0ffh ; set transmit data flag sacl tx_flag lac tx_data ; get data from memory andk 0fffch ; mask out bottom 2 bits sacl dxr ; write data to AIC b exit_tx_int send_1st lac init_flag ; increment init_flag addk 1 sacl init_flag lalk 03 ; start secondary communications sacl dxr exit_tx_int zals accl_st ; pop accumulator addh acch_st lst stat_st ; pop status reg eint ret ; ******************************************************************* ; Interrupts we're not interested in ; ******************************************************************* d_int ret rx_int ret tim_int ret INT0 ret INT1 ret INT2 ret .end