Freq generation
stilgar
Posts: 47
I need to generate 2 separate freq but they must be output on single pin and use only 1 cog. I need to generate a 123.50 Hz and a 82.41 Hz signal at the same time and mixed, to be output on P10.
I was looking at the OBEX " http://obex.parallax.com/object/244" file of Frequency Synthesis/PWM X8 but not sure if it can do what I need.
Thank you
I was looking at the OBEX " http://obex.parallax.com/object/244" file of Frequency Synthesis/PWM X8 but not sure if it can do what I need.
Thank you
Comments
-Phil
Hope this helps, not really familiar with tone gen on the propeller, onlt digital signals.
-Phil
Thank you
{{ Generates DTMF tones by combining two values retrieved from the sine lookup table The row tone and column tone are each updated once every degree 1KΩ I/O ─┳──────┳───────  0.1µF 0.01µf   }} CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 PUB Demo cognew(@DTMF_start,0) DAT org DTMF_start movi ctra,#%0_00110_000 ' Set duty mode movs ctra,#10 ' Output on pin 10 or dira,DTMF_mask mov row_target,row_delay add row_target,cnt mov column_target,column_delay add column_target,cnt :check_row mov cnt,row_target ' Determine if one degree has elapsed sub cnt,cnt cmps cnt,#0 wc if_nc jmp #:check_column add row_target,row_delay ' Increment time to next degree mov sine,row_angle ' Find value for this degree call #Get_sine mov t1,sine shl t1,#14 ' Shift into upper word, -2 to make room for other tone and zero-crossing call #Set_duty ' Set amplitude for this degree add row_angle,sine_step ' Increment angle to next degree :check_column mov cnt,column_target sub cnt,cnt cmps cnt,#0 wc if_nc jmp #:check_row add column_target,column_delay mov sine,column_angle call #Get_sine mov t2,sine shl t2,#14 call #Set_duty add column_angle,sine_step jmp #:check_row '---------------------------------------------------------------------------------------------------------------------- Get_sine test sine,sine_90 wc 'get quadrant 2|4 into c test sine,sine_180 wz 'get quadrant 3|4 into nz negc sine,sine 'if quadrant 2|4, negate offset or sine,sine_table 'or in sin table address >> 1 shl sine,#1 'shift left to get final word address rdword sine,sine 'read word sample from $E000 to $F000 negnz sine,sine 'if quadrant 3|4, negate sample Get_sine_ret ret '---------------------------------------------------------------------------------------------------------------------- Set_duty mov t3,t1 add t3,t2 add t3,zero_crossing mov frqa,t3 Set_duty_ret ret '---------------------------------------------------------------------------------------------------------------------- sine_table long $E000 >> 1 sine_90 long $800 sine_180 long $1000 zero_crossing long $8000_0000 sine_step long 32 ' 1 degree is 32 counts in the table row_delay long 2530 ' clkfreq / 123.5 / 256 = 2530.36 column_delay long 3792 ' clkfreq / 82.41 / 256 DTMF_mask long |< 10 sine res 1 row_angle res 1 row_target res 1 column_angle res 1 column_target res 1 t1 res 1 t2 res 1 t3 res 1 fitPhil Pilgrim (PhiPi) , thank you.