18F series performance not so good?

[mpgmike]

The PIC18F advantage over the 16F is more instructions. The 18F's ASM "MOVFF" allows transfer of a byte of data directly from one register to another. For the PIC16F, it would take several instructions using the W Register.

[CuriousOne]

Thanks!

So besides more peripherals, like USB host, 2x osc speed and 2x memory, there are no other advantages, right?

[tumbleweed]

Those extra instructions definitely make a difference. It's not just clock speed. If it takes more instructions to do the same thing then that's a disadvantage.

That, plus even though the memory is still banked you don't have the horrible ram arrangement that the PIC16 suffers from, and no program memory page issues.
The 18F has a hardware multiplier, dual-priority interrupts, more FSR registers.

All in all, if you have a choice between 16F and 18F, 18F is the better choice. It'll produce faster code in a lot of instances.
The only reasons I can think of to use a 16F might be price or perhaps power consumption.

[richard]

not to mention the flash memory is 16 bits wide allowing for tabled data to be accessed way easier, eliminating any need to pack/unpack data.
bigger faster fonts with less effort, works for me

[CuriousOne]

All that good, but does PBP uses them? The main difference I found is the dimension of arrays and long variables.
Say, average, 500 line PBP code will run significantly faster on 18F or not?
I don't care for banks or whatever with 16F - compiler takes care of.
Price is also not an issue - 18F45K80 and 16F1939 (which I most often use) have same price in china - around $3 new, $1 - 2nd hand.

[richard]

if you put a bowling club granny in a ferari would she drive faster ?

in the right hands a pic18 is faster by a large margin

[tumbleweed]

Say, average, 500 line PBP code will run significantly faster on 18F or not?
I don't care for banks or whatever with 16F - compiler takes care of.

I get that YOU don't care for banks or whatever, but the compiler does.

The answer depends on what your "average 500 line PBP code" does.
As you see from your original example of toggling IO ports, the difference could be anywhere from 0 to much faster.

How much faster?
It depends.

[Ioannis]

All that good, but does PBP uses them?

Yes it does.

You can vedrify this by yourself. Though a simple two variable multiplication in your editor and after compilation check the LST file. You will see that mulwf command is used just fine!

Ioannis

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2023 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 12/1/2023                                         *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************

b1   var byte
b2   var byte
w3   var word

b1=123
b2=456

w3=b1*b2

end

and part of the LST file:

                      00001 ;******************************************************************
                      00002 ;*  pbp_pic18FxxK40.LIB                                           *
                      00003 ;*                                                                *
                      00004 ;*  By        : Leonard Zerman, Jeff Schmoyer, Darrel Taylor,     *
                      00005 ;*              Charles Leo                                       *
                      00006 ;*  Notice    : Copyright (c) 2017 ME Labs, Inc.                  *
                      00007 ;*              All Rights Reserved                               *
                      00008 ;*  Date      : 04/05/2017                                        *
                      00009 ;*  Version   : 3.1.0                                             *
                      00010 ;*  Notes     : Created for 18FxxK40 and similar devices          *
                      00011 ;******************************************************************
                      00081   LIST
                      00082 ; Oscillator is 4MHz
                      01288   LIST
000000                01289     ORG RESET_ORG               ; Reset vector at 0
                      01298   LIST
000000 EF23 F000      01299         goto    INIT            ; Finish initialization
                      08250   LIST
000004 5004           08251 MUL     movf    R1, W
000006 0208           08252         mulwf   R3              ; R1 * R3 = PRODHL
000008 CFF3 F006      08253         movff   PRODL, R2
00000C CFF4 F007      08254         movff   PRODH, R2 + 1

[CuriousOne]

My code does various things - reads pixel data from eeprom and sends it to display module via paralel interface, to show meaningful data to user. It interacts with TCXO, ADCs, serial wired leds, mp3 module, GPS module and a lot of other I/O. My code does no complex math, except increasing value of some variables and doing HEX<>DEC conversion for RTC.

Here's a small fragment from one of my 16F code. So moving to 18F, will deliver any speed increase for something like this?

ERASER: 'INITIAL DISPLAY SET TO ZERO
low LED
FOR Y=0 TO 15
LOC=Y
GOSUB LOCSET
X=11
GOSUB CODER
NEXT 
pause 30
waiter: 'wait for keypress and display time
if lock=0 then goto beginner
pause 1000 'toggle led 
toggle led 
gosub gettime2
gosub timedisp
goto waiter 
stop 'finish


coder: 'decode into cd4543 bcd
low strb
PORTD.0=x.2
PORTD.1=x.1
PORTD.2=x.3
PORTD.3=x.0
high strb
return


LOCSET:' SET THE DIGIT LOCATION
HIGH STRB
PORTD.4=loc.0
PORTD.5=loc.1
PORTD.6=loc.2
PORTD.7=loc.3
LOW STRB
'PAUSE 10
RETURN


gettime:
   I2CRead SDA, SCL, $D0, $00, [RTCSec, RTCMin, RTCHour, RTCDay, RTCDate, RTCMonth, RTCYear, RTCCtrl]
   t1=rtchour >> 4 
   t2=rtchour // 16 
   t3=rtcMin >> 4 
   T4=rtcMin // 16
   'Z1=(RTCmin >> 4)*10+RTCmin // 16 'decode seconds
   'Z2=(RTCHour >> 4)*10+RTCHour // 16 'decode hours
hours=T1*10+T2
minutes=T3*10+T4
  if DRO<>rtcmin then  'check for time changes, so display only is refreshed when time is changed
  cvlileba=1
  else
  cvlileba=0
  endif 
  DRO=rtcmin
     Return