Re: Darrels interrupts and multiple SOUND statements, will it work?
Hi,
So, I've played around some more.....
It won't run at anything below 16MHz. Even at 16MHz the interrupt routine, executing at 10kHz cosumes 70% of the available CPU cycles.
I've only tried it on an 18F25K20 @64MHz, you try it on a 16F or 12F1840 and see if it works.
You can not cut'n'paste this into a program using DT-Ints. Try it stand-alone first and we'll see about DT-ints later - if needed.
/Henrik.
Code:'**************************************************************** '* Name : 3xSound generator.pbp * '* Author : Henrik Olsson * '* Notice : Written by Henrik Olsson 2015 * '* : Free software, use as you wish. * '* Date : 2015-01-14 * '* Version : 1.0 * '* Notes : Written in response to a thread on the PBP forum: * '* : www.picbasic.co.uk/forum/showthread.php?t=19684 * '* * '* : Tones are generated using the DDS tecnique with a * '* simple 16bit accumulator to which a value gets * '* added once every interrupt (100us). When the * '* accumulator overflows the output is toggled. * '* Three generators are incorporated since that was * '* the request. More could be added if the PIC is * '* clocked fast enough. With three generators 16MHz * '* is the lowest you want to use. The interrupts * '* then uses ~70% of the available CPU cycles when * '* three tones are generated. * '* * '* Version history: * '* v1.0 2015-01-14 - Initial version * '* * '**************************************************************** ' CONFIG's, TRIS's, ANSEL's CMCON's and anything device specific is not shown DEFINE OSC 64 DEFINE INTHAND Generate ' We're treating the interrupt as an ASM routine (see notes!) '------------------------------------------------------------------------------------------- ' These variables and alises are needed by the sound generator and needs to be ' accessed by the user. Channel_1 VAR PortC.0 ' Output for sound channel 1 Channel_2 VAR PortC.1 ' Output for sound channel 2 Channel_3 VAR PortC.2 ' Output for sound channel 3 TMR2IF VAR PIR1.1 ' Alias to TMR2 Interrupt Request Flag - verify against datasheet. Output_1 VAR WORD ' Desired output frequency, Channel 1, 13.107 units per Hz Output_2 VAR WORD ' Desired output frequency, Channel 2, 13.107 units per Hz Output_3 VAR WORD ' Desired output frequency, Channel 3, 13.107 units per Hz Duration_1 VAR WORD ' Duration of tone, Channel 1, 100us units. Duration_2 VAR WORD ' Duration of tone, Channel 2, 100us units. Duration_3 VAR WORD ' Duration of tone, Channel 3, 100us units. '------------------------------------------------------------------------------------------- ' These are variables used by the interrupt service routine. ' No user servicable parts inside...... R0_SHADOW VAR WORD ' Variable used for saving PBP system variables in the ISR R1_SHADOW VAR WORD ' Variable used for saving PBP system variables in the ISR R4_SHADOW VAR WORD ' Variable used for saving PBP system variables in the ISR Accumulator_1 VAR WORD ' DDS accumulator for sound generator 1 Accumulator_2 VAR WORD ' DDS accumulator for sound generator 2 Accumulator_3 VAR WORD ' DDS accumulator for sound generator 3 old_1 VAR WORD ' Used to detect overflow of accumulator 1 old_2 VAR WORD ' Used to detect overflow of accumulator 2 old_3 VAR WORD ' Used to detect overflow of accumulator 3 '-------------------------------------------------------------------------------------------- ' We want 10kHz interrupt rate, that's 100us between interrupts. ' The interrupt routine needs around ~280 instruction cycles when ' outputting on three channels. ' ' At 16MHz that would be 400 instructions - 70% used by the generator. ' At 20MHz that would be 500 instructions - 56% used by the generator ' At 40MHz that would be 1000 instructions - 28% used by the generator ' At 64MHz that would be 1600 instructions - 17.5% used by the generator ' ' T2CON and PR2 needs to be setup so that an interrupt is triggered every 100us ' Use one of the follwing: ' PR2 = 99 : T2CON = %00000110 ' For 64MHz - 1:16 prescaler ' PR2 = 49 : T2CON = %00000110 ' For 32MHz - 1:16 prescaler ' PR2 = 124 : T2CON = %00000101 ' For 20MHz - 1:4 prescaler ' PR2 = 99 : T2CON = %00000101 ' For 16MHz - 1:4 prescaler PR2 = 99 : T2CON = %00000110 'TMR2 on, postscaler 1:1, prescaler 1:4 IPR1.1 = 1 ' TMR2 high priority PIE1.1 = 1 ' TMR2 IE INTCON.6 = 1 ' PIE INTCON.7 = 1 ' GIE Main: ' All three notes will play simultanously for the specified duration. ' The sound is generated in the background so the PAUSE 1000 will ' execute at the same time as the notes are played. Remember though that ' the interrupt "steals" time so the PAUSE isn't correct. The slower the ' PIC clock is the more inacurate it gets. Output_1 = 857 : Duration_1 = 500 'Play C2 (65.4Hz) for 50ms Output_2 = 5767 : Duration_2 = 2500 'Play A4 (440.0Hz)for 250ms Output_3 = 25893 : Duration_3 = 1000 'Play B6 (1975.5Hz) for 100ms Pause 1000 Goto Main '------------------------------------------------------------------------------- ' Actual interrupt routine here. Please note that this is written in PBP but ' the interrupt is handled as if it were a ASM interrupt. As far as I can see ' it uses PBP system variables R0, R1, R4 so I'm saving/restoring those. ' If ANY code gets added here then the ASM-listning needs to be checked to ' see of the added PBP code uses any more system variables and if so ' those needs to saved/restored as well. ' When all three channels produces output it needs ~280 instructions cycles. @ Generate: @ MOVE?WW R0, _R0_SHADOW ; Save PBP system variable R0 @ MOVE?WW R1, _R1_SHADOW ; Save PBP system variable R1 @ MOVE?WW R4, _R4_SHADOW ; Save PBP system variable R4 TMR2IF = 0 IF Duration_1 > 0 THEN Accumulator_1 = Accumulator_1 + Output_1 If Accumulator_1 < old_1 THEN Toggle Channel_1 old_1 = Accumulator_1 Duration_1 = Duration_1 - 1 ELSE Channel_1 = 0 ENDIF IF Duration_2 > 0 THEN Accumulator_2 = Accumulator_2 + Output_2 If Accumulator_2 < old_2 THEN Toggle Channel_2 old_2 = Accumulator_2 Duration_2 = Duration_2 - 1 ELSE Channel_2 = 0 ENDIF If Duration_3 > 0 THEN Accumulator_3 = Accumulator_3 + Output_3 If Accumulator_3 < old_3 THEN Toggle Channel_3 old_3 = Accumulator_3 Duration_3 = Duration_3 - 1 ELSE Channel_3 = 0 ENDIF @ MOVE?WW _R0_SHADOW, R0 ; Restore PBP system variable R0 @ MOVE?WW _R1_SHADOW, R1 ; Restore PBP system variable R1 @ MOVE?WW _R4_SHADOW, R4 ; Restore PBP system variable R4 @ retfie FAST '------------------------------------------------------------------------------- END
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