High priority/low priority program parts

[mpgmike]

ON INTERRUPT works just fine, especially when you are only using one interrupt. For multiple INTERRUPTs, your ISR does nothing more than filter through possible Flags & sends the code where it needs to go.

Not sure what all you're controlling, but HPWM can control your coolant fan, with temperature thresholds for duty cycle. Reading the analog port only takes maximum 50 uS (microseconds). If no change in temperature, no change to the HPWM DC%. As for fuel pump Duty Cycle%, what are you using to determine your needs? I would use either a pressure sensor (some of the newer vehicles have them built into the fuel rail) with a MAP where you are maintaining a constant absolute pressure, or perhaps just TPS. Absolute pressure is way more accurate and would be less likely to cause a lean condition at WOT.

May I suggest using something like a PIC18F46K22. It is a 40-pin device. You have an entire PORTB to control your LCD, it has plenty of analog channels, plus it has 5 CCP/PWM modules. Use one Analog port for your ECT, one for MAP, one for Fuel Pressure, and perhaps one for TPS. Controlling the fan is rather simple using SELECT CASE CTS
CASE IS < 90 : HPWM 1, 0, 1000
CASE IS < 100 : HPWM 1, 127, 1000
CASE ELSE : HPWM 1, 200, 1000
END SELECT

For fuel pressure & MAP you'll need to find what voltages equate to what pressures. If turbo, you're probably using at least a 2-BAR MAP. With a 5 volt VREF, anything above 2.5 volts and you have boost. You probably need about 2.4 BAR of fuel pressure.
Duty VAR BYTE
IF (Fuel_Value) < (MAP) THEN
Duty = Duty + 1
HPWM 2, DUTY, 1000
ENDIF

Of course this is rather simplified as you need to do the conversions before comparing.

If you can get by with 28 pins, the PIC18F26K22 is the same basic MCU but with fewer pins.

[Mugelpower]

Hello mpgmike,

you are totally right. Problem is: I already made the PCB for this double-PIC Project and it works halfways.
If I had to begib new i would take your advice and get the 18F26k22. Maybe I got some liying around.
I bought 18F45K... for a projekt Henrik supports me but this device is too big in pin-through case form. Its HUUUGE
compared to a 18F1320 in SMD which I have.
It took me days to develop the PCB and manufacture it and I think optimizing the program is way less work
than starting new.Next thing is : I try the HSEROUT/HSERIN thingy and watch if the cycle gets faster.
I don´t have as much leisure time as I would like to.

[HenrikOlsson]

HSERIN/HSEROUT won't make any difference on it's/their own.

You need to look at the system level. Why is this code taking up to 300ms to execute? Because it sits here waiting for data for 300ms Before continuing (if no data arrives). So, the next question then is what is the F88 doing and how often does it actually SEND data?

And again, think about implementing some handshaking or polling scheme.

/Henrik.

[Mugelpower]

hello Henrik,
I thought HSERIN/HSEROUT would automatcally take care of the handshake. In the background.

On the other hand i could put some more debug commands into the 16F88 code so that it has for example

3 Debug commands between the main program lines. That should translate to 3 times sending the same which
translates to less waiting of the 18F1320 to get what it wants.It doesn´t matter that this will slow down the 16F88, it has the slow task.

Haha! Thats the total primitive method. I guess you will call it "Flintstone style programming".

[HenrikOlsson]

No, HSERIN/HSEROUT does not do handshaking automatically, in the background.
The UART in the PIC can receive one byte/character (and almost a second full byte/character) without the code doing anything but when that byte/character is received the code must fetch the byte from the receive buffer. This is where interrupts come in but you you were quite clear you didn't want to go that route - and frankly, it should not be needed for this.

And again, using HSERIN with a WAIT statement in place of DEBUGIN will gain you pretty much nothing.

Can you post the '88 code for us to take a look at, I'm sure you'll get plenty of suggestions on how to improve it.

/Henrik.

[Mugelpower]

Hello Henrik,
thank you for your suggestion
here:

'************************************************* ***************
'* Name : PUMP16F88V1 *
'* Test with 20-23 °C RB0 = HPWM out *
'* Author : M.David *
'* Notice : Copyright (c) 2018 *
'* : All Rights Reserved *
'* Date : 01.01.2018 *
'* Version : AB sensor M12x1,5 *
'* Notes : 16F88 kein LCD funktioniert halbwegs *
'* : PORTA.0 analog IN 0-2V channel 0 *
'* PORTB.1 Fan out PPORTB.0 Water pump out *
'************************************************* ***************

#CONFIG
__config _CONFIG1,_EXTCLK & _WDT_ON & _LVP_OFF & _CP_OFF
#ENDCONFIG
Define OSC 20
TRISB = %00000000

Define ADC_BITS 8 ' Set number of bits in result
Define ADC_CLOCK 3 ' Set clock source (3=rc)
Define ADC_SAMPLEUS 50 ' Set sampling time in uSec
DEFINE DEBUG_REG PORTB
DEFINE DEBUG_BIT 2
DEFINE DEBUG_BAUD 19200
DEFINE DEBUG_MODE 0
DEFINE DEBUG_PACING 500

define CCP1_REG PORTB 'für HPWM
DEFINE CCP1_bit 0 'HPWM port B.0


TRISA = %11111111 ' Set PORTA to all input
ADCON1 = %00000010 ' Set PORTA analo
CMCON = 7 ' Disable analog comparator
ANSEL = %00000001 ' set AN0 (RA0) as analog, others to digital




FAN VAR PORTB.1
Uin VAR Word
Temp Var word
speed var word
Pump var word
RX var word
RS var word
B0 var word

Speed = 0
FAN = 0
pause 1000
DEBUG 10,13

main:

ADCIN 0,Uin ' Read channel 0 (RA)

DEBUG "*.*",DEC3 RX,dec3 RS,dec1 FAN,13,10 ' dec3 is important
DEBUG 10,13
HPWM 1,speed,2442

IF Uin => 64 then
B0 = Uin/2
Temp = 100-B0
else
Temp = 131 - Uin
endif
TEMP = Temp-5 ;Korrekturfaktor nach Kalibrierung Anzeige ok bei 75-90°C


RX = TEMP
RS = pump


Select Case temp
Case is < 67
speed = 0
pump = 0
case 68, 69, 70, 71, 72
speed = 8
pump = 3
case 73, 74
speed = 16
pump = 6
case 75, 76
speed = 32
pump = 12
case 77, 78
speed = 64
pump = 25
case 79, 80
speed = 124
pump = 50
case 81,82
pump = 75
Speed = 191
case is > 80
speed = 255
pump = 100
End Select

IF (Temp <= 84 ) then
FAN = 0
else
FAN = 1
endif

goto main

END ' End of program

[Mugelpower]

Here three pics of that housing and so on: