Aquarium Lighting project - PWM - Need some assistance as I'm rusty !

Hi Guys, been a while since I was here, hope everyone is OK and would firstly like to wish everyone the complements of the season.

Some of you may remember the vivarium project I developed with the help of Darrel, and Henrik. I'm pleased to say the unit is still running and keeping my snakes nice and warm. It hasn't missed a beat in all these years. Anyway, I digress slightly, I'm looking at developing another controller for a marine fish tank, based on the same chip and same PCB as I still have a few left over. Most of the code will be harvested from the thermostat project, but one area that has had my grey hair turning white is the PWM aspect, which is where I'm seeking some assistance.

Basics:
PIC 18F4580 - running with a 20mhz Xtal - programmed with the HS-PPL config fuse (PIC is maxed out at 40 Mhz)
DS1307 RTC
Port B6 and B7 to be PWM

The RTC data has been converted into decimal, so I have two variables TimeH and TimeM for hours and minutes in 24Hr format. These are used to set the case for the lighting period for two channels. Each of the two channels will have a Dawn, Day, Dusk and Night period, so for example Dawn could be 08:00 - 09:15, Day then from 09:15 - 17:00, Dusk from 17:00 - 18:30 and Night from 18:30 - 08:00 the next day. The idea is to fade up the lights whilst in the Dawn period, run them at max in the day, then fade them down in the Dusk period with them being off at night. As I'm not using the hardware PWM and opting for software control, and it's been several years since I last touched PBP I'm somewhat rusty on how to resolve the issue of incrementing the PWM duty variable so that it rises and falls from 0 to 255 (and then 255 - 0) over whatever time period is set for Dawn and Dusk. So in the above example, it would fade up from 0 to 255 over the course of 75 minutes. If the Dawn period was extended say between 08:00 and 09:30, then it would need to fade over 90 minutes. The frequency of the cycles needs to be 500 htz as well.

I've picked up one suggestion from someone who built a similar project, and have modified the code as such

Code:

Vb_5 = ((b_fade_in.highbyte * 60) + b_fade_in.lowbyte) *60 'Get total duration time in seconds Vb_6 = B_Max - B_Min 'Work out the 'distance' the lights go from min to max B_Fadein_Time = Vb_5 / Vb_6 'Get number of seconds between each PWM change Vb_7 = Vb_5 // Vb_6 'Get fractions of a second if Vb_7 >=5 then B_Fadein_Time = B_Fadein_Time + 1 'If its over half a second then round up Vb_5 = ((B_Fade_Out.highbyte * 60) + B_Fade_Out.lowbyte) *60 B_Fadeout_Time = Vb_5 / Vb_6 Vb_7 = Vb_5 // Vb_6 'Get fractions of a second if Vb_7 >=5 then B_Fadeout_Time = B_Fadeout_Time + 1 'If its over half a second then round up

Vb_7 holds the variable in seconds which I've tested by changing the period for Dawn and Dusk. But I'm at a loss how to use this to increment the variable (B_PWM) between 0 and 255. I know I need to increment B_PWM by one every Vb_7 seconds, but just can't seem to get my head round it.

Here's the full code

Code:

'**************************************************************** '* Name : Aquarium LED Lighting controller. * '* Author : M. Crabbe * '* Notice : Original Code by M Jervice * '* : 18F2550 * '* Date : * '* Version : 1.0 * '* Ported to the 18F4580 * '* By Malcolm Crabbe * '* 09/12/2012 * '* Ver 1.1 - B * '* * '**************************************************************** @ errorlevel -205 ASM __CONFIG _CONFIG1H, _OSC_HSPLL_1H __CONFIG _CONFIG2L, _PWRT_ON_2L __CONFIG _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H __CONFIG _CONFIG3H, _PBADEN_OFF_3H __CONFIG _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L ENDASM DEFINE OSC 40 ; config settings 18F4580, 20mhz crystal ADCON1 = $0F clear DEFINE LCD_DREG PORTB ' LCD Data port DEFINE LCD_DBIT 0 ' starting Data bit (0 or 4) DEFINE LCD_EREG PORTB ' LCD Enable port DEFINE LCD_EBIT 5 ' Enable bit (on EasyPIC 5 LCD) DEFINE LCD_RSREG PORTB ' LCD Register Select port DEFINE LCD_RSBIT 4 ' Register Select bit (on EasyPIC 5 LCD) DEFINE LCD_BITS 4 ' LCD bus size (4 or 8 bits) DEFINE LCD_LINES 4 ' number of lines on LCD DEFINE LCD_COMMANDUS 2000 ' Command delay time in us DEFINE LCD_DATAUS 50 ' Data delay time in us '******************************************************************************* CMCON = 7 ' disable Comparators ADCON1 = %00001011 ' sets up Analogue pins ADCON2.7 = 1 TRISA = %00001111 TRISB = %00000000 TRISD = %00001111 TRISE = %1111 '******************************************************************************* i var word 'Misc counter iv var word LCD_Mode var word 'LCD light mode LCD_Timer var word 'Timer for how long the LCD is on for. LCD_Time var word 'Counter for the timer LCD_Tmr var word '******************************************************************************* ' RTC Variables '******************************************************************************* SCLpin var PORTC.3 ' RTC pin - clk SDApin var PORTC.4 ' RTC pin - data RTC_Msecs var byte RTC_Secs var byte RTC_Mins var byte RTC_Hours var byte RTC_Day var byte RTC_WDay var byte RTC_Month var byte RTC_Year var byte RTC_Ctrl var byte dummy var byte RTclock var byte[8] Tick_Tmr var byte Hours var byte Minutes var byte TimeH var byte ' Variable to store current hour TimeM var Byte ' Variable to store current minutes CounterA var byte ' General purpose Variable CounterB var byte ' General purpose Variable CounterC var byte ' General purpose Variable CounterD var byte ' General purpose Variable '******************************************************************************* ' LED variables ' Whites: '******************************************************************************* W_Min var word 'Min Light value W_Max var word 'Max Light value W_Fade_In var word 'Fade in duration W_Fade_Out var word 'Fade out duration W_Dawn_On_H var word 'What time to turn the lights on W_Dawn_On_M var word 'What time to turn the lights on W_Day_On_H var word 'What time to turn the lights on W_Day_On_M var word 'What time to turn the lights on W_Dusk_On_H var word 'What time to turn the lights on W_Dusk_On_M var word 'What time to turn the lights on W_On_H var word 'What time to turn the lights on W_On_M var word 'What time to turn the lights on W_Off_H var word 'Time to turn lights off W_Off_M var word 'Time to turn lights off '******************************************************************************* ' LED variables ' Blues: '******************************************************************************* B_Min var word 'Min Light value B_Max var word 'Max Light value B_Fade_In var word 'Fade in duration B_Fade_Out var word 'Fade out duration B_Dawn_On_H var word 'What time to turn the lights on B_Dawn_On_M var word 'What time to turn the lights on B_Day_On_H var word 'What time to turn the lights on B_Day_On_M var word 'What time to turn the lights on B_Dusk_On_H var word 'What time to turn the lights on B_Dusk_On_M var word 'What time to turn the lights on B_On_H var word 'What time to turn the lights on B_On_M var word 'What time to turn the lights on B_Off_H var word 'Time to turn lights off B_Off_M var word 'Time to turn lights off 'Running fade variables B_FadeIn_Time var word 'LIVE fade delay time seconds B_FadeOut_Time var word W_FadeIn_Time var word W_FadeOut_Time var word B_Cnt var word 'Seconds counter for the timing of adjusting the PWM W_Cnt var word B_Tick var word W_Tick var word 'PWM Variables where the current output values are stored W_PWM var word 'Whites B_PWM var word 'Royal Blues '******************************************************************************* Blue_Day_Cycle var word 'Store for which part of the day cycle we are in White_Day_Cycle var word ' Constants for the current running mode cycle for the lights DAWN con 0 DAY con 1 DUSK con 2 NIGHT con 3 '******************************************************************************* 'Expendable variables used for misc calculations etc Vw_5 var word Vw_6 Var word Vw_7 var word Vw_8 var word Vb_5 var word Vb_6 Var word Vb_7 var word Vb_8 var word '******************************************************************************* data @0 data 08 'Whites dawn ON Time HOURS data 00 'Whites dawn ON Time MINS Data 11 'Whites day ON time Hours Data 00 'Whites day ON time Minutes Data 16 'Whites dusk ON time Hours Data 00 'Whites dusk On time Mins data 20 'Whites OFF Time HOURS data 00 'Whites OFF Time MINS data 0 'Whites MIN Intensity % data 75 'Whites MAX Intensity % data 08 'Blue dawn ON Time HOURS data 00 'Blue dawn ON Time MINS Data 08 'Blue day ON time Hours Data 01 'Blue day ON time Minutes Data 08 'Blue dusk ON time Hours Data 02 'Blue dusk On time Mins data 08 'Blue OFF Time HOURS data 03 'Blue OFF Time MINS data 0 'Blue MIN Intensity % data 100 'Blue MAX Intensity % Data 08 'Blue On Hours Data 30 'Blue On Min Data 08 'White On Hrs Data 30 'White on Min data 00 'Blue ON time hours data 01 'Blue ON time Mins Data 00 'White ON time hours Data 01 'White ON time mins '******************************************************************************* 'Setup Interrupts '******************************************************************************* INCLUDE "DT_INTS-18.bas" ; Base Interrupt System INCLUDE "ReEnterPBP-18.bas" ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler TMR1_INT, _MyTimer, PBP, yes endm INT_CREATE ; Creates the interrupt processor endasm T1CON = %10000001 ; free-running, 1:1 prescaler @ INT_ENABLE TMR1_INT ; enable Timer1 interrupts '******************************************************************************* ' Start the program '******************************************************************************* code_start: SetupPreset: RTC_Msecs=$00 ' Seconds preset to 00 RTC_Secs=$00 ' Seconds preset to 00 RTC_Mins=$59 ' Minutes preset RTC_Hours=$07 ' Hours preset RTC_WDay=$01 ' Weekday preset to 01 RTC_Day=$12 ' Day preset 12 RTC_Month=$06 ' Months preset to June RTC_Year=$02 ' Year preset to 2002 RTC_Ctrl=$10 ' Control preset to output 1 second 'Tick' on SQWpin I2CWrite SDApin,SCLpin,$D0,$00,[RTC_Secs,rtc_mins,RTC_Hours,RTC_Ctrl] B_Cnt = 0 W_Cnt = 0 gosub read_eeprom 'Read in the data needed for the lighting periods LCD_Mode = 3 'LCD Backlight always ON gosub Calc_Fade '******************************************************************************* 'Main program loop '******************************************************************************* main: gosub Read_Clock_2 if B_Dawn_On_H < TimeH and B_Dawn_On_M <= TimeM Then Blue_Day_Cycle = NIGHT endif if B_Dawn_On_H = TimeH and B_Dawn_On_M = TimeM Then Blue_Day_Cycle = DAWN endif if B_Day_On_H = TimeH and B_Day_On_M = TimeM then Blue_Day_Cycle = DAY endif if B_Dusk_On_H = TimeH and B_Dusk_On_M = TimeM then Blue_Day_Cycle = Dusk endif if B_Off_H = TimeH and B_Off_M = TimeM then Blue_Day_Cycle = Night endif if W_Dawn_On_H < TimeH and W_Dawn_On_M < TimeM Then White_Day_Cycle = NIGHT endif if W_Dawn_On_H = TimeH and W_Dawn_On_M = TimeM Then White_Day_Cycle = DAWN endif if W_Day_On_H = TimeH and W_Day_On_M = TimeM then White_Day_Cycle = DAY endif if W_Dusk_On_H = TimeH and W_Dusk_On_M = TimeM then White_Day_Cycle = Dusk endif if W_Off_H = TimeH and W_Off_M = TimeM then White_Day_Cycle = Night endif ;*************************** '*** Do BLUE daily cycle *** ;*************************** select case Blue_Day_Cycle case DAWN lcdout $FE,$94,"BLUE: DAWN " if B_cnt = B_Fadein_time and B_PWM < B_Max then B_PWM = B_PWM + 1 B_Cnt = 0 endif if B_PWM >= B_Max then Blue_Day_Cycle = DAY endif case DAY lcdout $FE,$94,"BLUE: DAY " B_PWM= B_Max B_Cnt = 0 CASE DUSK lcdout $FE,$94,"BLUE: DUSK " if B_Cnt >= B_Fadeout_time and B_PWM > B_Min then B_PWM = B_PWM - 1 B_Cnt = 0 endif if B_PWM = b_min then Blue_Day_Cycle = NIGHT endif case NIGHT lcdout $FE,$94,"BLUE: NIGHT" B_Cnt = 0 B_PWM=0 end select ;**************************** '*** Do WHITE daily cycle *** ;**************************** select case White_Day_Cycle case DAWN lcdout $FE,$D4+8,"White: DAWN " if W_Cnt = W_Fadein_time and W_PWM <= W_Max then W_PWM = W_PWM + 1 W_Cnt = 0 endif if W_PWM >= W_Max then White_Day_Cycle = DAY endif case DAY lcdout $FE,$D4+8,"White: DAY " White_Day_Cycle = DUSK W_Cnt = 0 CASE DUSK lcdout $FE,$D4+8,"White: DUSK " if W_Cnt >= W_Fadeout_time and W_PWM > W_Min then W_PWM = W_PWM - 1 W_Cnt = 0 endif if W_PWM = B_Min then White_Day_Cycle = NIGHT endif case NIGHT lcdout $FE,$D4+8,"White: NIGHT" W_Cnt = 0 end select ;****************************** ;*** Display Results on LCD *** ;****************************** 'for test pourpose only lcdout $FE,$80,#vb_5," ",#vb_6," ",#vb_7 lcdout $FE,$C0,#B_PWM Pwm PORTD.7,B_PWM,1 'D7 used for EasyPIC5 development board - will be changed to RB7 goto main Calc_Fade: ';******************************************************************************* '' LED Fade calculations '' This routine takes the fade in/out durations and also the min/max '' LED power values and calculates what the duration is between '' changing the PWM value to give us a smooth fade from min to max ';******************************************************************************* Vb_5 = ((b_fade_in.highbyte * 60) + b_fade_in.lowbyte) *60 'Get total duration time in seconds Vb_6 = B_Max - B_Min 'Work out the 'distance' the lights go from min to max B_Fadein_Time = Vb_5 / Vb_6 'Get number of seconds between each PWM change Vb_7 = Vb_5 // Vb_6 'Get fractions of a second if Vb_7 >=5 then B_Fadein_Time = B_Fadein_Time + 1 'If its over half a second then round up Vb_5 = ((B_Fade_Out.highbyte * 60) + B_Fade_Out.lowbyte) *60 B_Fadeout_Time = Vb_5 / Vb_6 Vb_7 = Vb_5 // Vb_6 'Get fractions of a second if Vb_7 >=5 then B_Fadeout_Time = B_Fadeout_Time + 1 'If its over half a second then round up Vw_5 = ((W_Fade_In.highbyte * 60) + W_Fade_In.lowbyte) *60 Vw_6 = W_Max - W_Min W_Fadein_Time = Vw_5 / Vw_6 Vw_7 = Vw_5 // Vw_6 'Get fractions of a second if Vw_7 >=5 then W_Fadein_Time = W_Fadein_Time + 1 'If its over half a second then round up Vw_5 = ((W_Fade_Out.highbyte * 60) + W_Fade_Out.lowbyte) *60 W_Fadeout_Time = Vw_5 / Vw_6 Vw_7 = Vw_5 // Vw_6 'Get fractions of a second if Vw_7 >=5 then W_Fadeout_Time = W_Fadeout_Time + 1 'If its over half a second then round up return 'Lets say 2 hours (120 mins) & 191 for the fade amount (ie 0 to 255 or 0% to 100% intensity) 'So we need to do: ' convert hours into minutes, then add minutes and then multiply by 60 to convert to seconds ' so: 2 hours = 120 mins + 0 mins * 60 to get 7200 seconds ' The distance is now based on the converted % into the PWM range of 0-255 ' calculate the 'distance' the light goes from min to max (0 to 255 in this eg: 75% = 191 so: 191- 0 = 191) ' now divide total seconds by 'distance' ie: 7200 / 191 = 37.69 seconds between each PWM change ' Now we test the milliseconds and if above .5 we round up to the next second ;******************************************************************************* ' Read Eeprom data into variables ;******************************************************************************* Read_eeprom: read 0,W_Dawn_On_H 'Whites ON time hours read 1,W_Dawn_On_M 'Whites ON time minutes Read 2,W_Day_On_H Read 3,W_Day_On_M read 4,W_Dusk_On_H Read 5,W_Dusk_On_M Read 6,W_Off_H Read 7,W_Off_M Read 8,W_Min Read 9,W_Max read 10,B_Dawn_On_H 'Whites ON time hours read 11,B_Dawn_On_M 'Whites ON time minutes Read 12,B_Day_On_H Read 13,B_Day_On_M read 14,B_Dusk_On_H Read 15,B_Dusk_On_M Read 16,B_Off_H Read 17,B_Off_M Read 18,B_Min Read 19,B_Max read 20,B_On_H Read 21,B_On_M read 22,W_On_H Read 23,W_On_M read 24,w_fade_in.highbyte 'Whites fade IN duration hours read 25,w_fade_in.lowbyte 'Whites fade IN duration minutes read 26,b_fade_out.highbyte 'Whites fade IN duration hours read 27,b_fade_out.lowbyte 'Whites fade IN duration minutes W_Min = (W_Min *255)/100 'Convert intensity % to real PWM value (from 0-100% to 0-255) W_Max = (W_Max *255)/100 B_Min = (B_Min *255)/100 B_Max = (B_Max *255)/100 gosub Read_Clock_2 return ;******************************************************************************* MyTimer: Tick_Tmr = Tick_Tmr + 1 'pause 100 if Tick_Tmr >179 then Tick_Tmr = 0 B_Cnt = B_Cnt + 1 W_Cnt = W_Cnt + 1 endif @ INT_RETURN ;******************************************************************************* '**** Ds1307 RTC Clock **** ;******************************************************************************* Read_Clock_2: I2CRead SDApin,SCLpin,$D0,$00,[RTC_Secs,rtc_mins,rtc_hours,RTC_Ctrl] ; read DS1307 chip If RTC_Hours.6=1 then CounterA=(RTC_Hours>>4)&$01 ' Work-Out 12 or 24 hour Display for Hours else CounterA=(RTC_Hours>>4)&$03 endif CounterA=CounterA*10+(RTC_Hours&$0F) ' Display Hours appropriately for 12 or 24 hour Mode If RTC_Hours.6=1 then LCDOut $FE,$D4,#CounterA else LCDOut $FE,$D4,#CounterA Dig 1,#CounterA Dig 0 endif LCDOut ":",#(RTC_Mins>>4)&$0F,#RTC_Mins&$0F TimeH=(RTC_Hours>>4) 'convert the BCD format of the hours register and store in variable timeH TimeH=(TimeH &$03)*10 TimeH=TimeH+(RTC_Hours&$0F) TimeM=(RTC_Mins>>4) TimeM=(TimeM &$07)*10 TimeM=TimeM+(RTC_Mins&$0F) 'convert the BCD format of the mins register and store in variable timeM Return

Re: Aquarium Lighting project - PWM - Need some assistance as I'm rusty !

I found DT's slow PWM (http://www.pbpgroup.com/modules/wfse...hp?articleid=6) maybe that would be the answer ??

Re: Aquarium Lighting project - PWM - Need some assistance as I'm rusty !

OK I've re-written the code to use the multiple spwm routine produced by DT, but still can't get the delay working right.

This is the routine that calculates the fade (or pause duration) for the dutycycle

Code:

Fade: Vb_1 = ((B_Day_On_H - B_Dawn_On_H)*60) ' difference between day start and dawn start hour, converted to min Vb_2 = (B_Day_On_M - B_Dawn_On_M) ' difference between day start and dawn start mins Vb_5 = (Vb_1+Vb_2)*60 ' Get total duration time in seconds Vb_6 = B_Max - B_Min ' Work out the 'distance' the lights go from min to max B_Fadein_Time = Vb_5 / Vb_6 ' Get number of seconds between each PWM pulse

Setting the dusk start time to 8:00 and the day on time to 8:05 I get the following results for the variables (B_Min = 0 and B_Max = 255) on the LCD

Vb_5 = 600
Vb_6 = 255
B_Fadein_time = 2

I then have the following statement which should increment the duty cycle until it reaches 255, with each cycle paused 2 seconds

Code:

case DAWN lcdout $FE,$94,"BLUE: DAWN " DutyCycle1 = DutyCycle1 +1 pause B_Fadein_Time if DutyCycle1=B_Max then Blue_Day_Cycle = DAY endif

However when run the duty cycle cycles from 0 to 255 so fast you can hardly notice it. Right, so the pause 2 statement is going to be too low, as pause 1000 equates to 1 second, so I multiplied the result by 1000 - the net result was too slow, it never reached 255 by the time the 5 minutes were up. Doing the maths I need to divide 600 seconds by 255 steps = 2.352941176470588. So I really need to convert this to a manageable number, say 2.353. ( B_Fadein_time is a word variable so should be able to store that result), and then convert this into seconds to use in the delay loop, but in a way that actually works !

Assistance would be appeciated

Re: Aquarium Lighting project - PWM - Need some assistance as I'm rusty !

Seems this place is not what it used to be... almost a 100 views and not one comment or suggestion. :(

Re: Aquarium Lighting project - PWM - Need some assistance as I'm rusty !

This may be of little help but the upcoming FineLineIDE detected 3 unused labels:
Ln 213 code_start:
Ln 215 SetupPreset:
Ln 463 MyTimer:

Norm

Re: Aquarium Lighting project - PWM - Need some assistance as I'm rusty !

Quote:

Originally Posted by Normnet

This may be of little help but the upcoming FineLineIDE detected 3 unused labels:
Ln 213 code_start:
Ln 215 SetupPreset:
Ln 463 MyTimer:

Norm

Thanks for the comment, but as you say, not a lot of help. The first two simply are place makers... the latter is a routine that exists as a subroutine prior to the clock read routine and is referenced as part of the setup of the interrupts - I'll think I'll stick to Microcode Studio as my IDE ;-)