Post by thread:[PICLIST] From 16F84 to 16F877

Hello, i'm working with a LCD (HD44780, 2x16 4 wire mode) i used code from called WKTIM4M.ASM (thx :). This worked great with a 16F84 but now i want to use it at an 16F877 but it won't work. Am i doing something wrong here? ;----------------------------------------------------------------------; ; Initialize the ports ; ;----------------------------------------------------------------------; init: clrf PORTE clrf PORTD bsf STATUS, RP0 movlw B'00000000' ; RE all as outputs movwf TRISE movlw B'00001111' ; RD7-RD4 outputs others Input movwf TRISD bcf STATUS, RP0 return ================================================================ Thanks for reading this far... Aart. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Aart wrote: {Quote hidden}> > Hello, > > i'm working with a LCD (HD44780, 2x16 4 wire mode) i used code from called WKTIM4M.ASM (thx :). This worked great with a 16F84 but now i want to use it at an 16F877 but it won't work. > > Am i doing something wrong here? > > ;----------------------------------------------------------------------; > ; Initialize the ports ; > ;----------------------------------------------------------------------; > init: > clrf PORTE > clrf PORTD > > bsf STATUS, RP0 > movlw B'00000000' ; RE all as outputs > movwf TRISE > movlw B'00001111' ; RD7-RD4 outputs others Input > movwf TRISD > bcf STATUS, RP0 > > > return > ================================================================ PORTE will be in ANALOG mode. Change the ADCON1 register to make it work in digital mode. bsf STATUS,RP0 movlw 6h ; all analog pins = digital movwf ADCCON1 bcf STATUS,RP0 Make sure the unused pins on the other ports are set as outputs. -- Best regards Tony mICros http://www.bubblesoftonline.com spam_OUTsalesTakeThisOuTpicnpoke.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> > i'm working with a LCD (HD44780, 2x16 4 wire mode) i used code from >called WKTIM4M.ASM (thx :). This worked great with a 16F84 but now i want >to use it at an 16F877 but it won't work. > > bsf STATUS, RP0 > > movlw B'00000000' ; RE all as outputs > > movwf TRISE > > movlw B'00001111' ; RD7-RD4 outputs others Input > > movwf TRISD > > bcf STATUS, RP0 This probably doesn't affect anything you're doing here, but it's worth mentioning that in changing from a 16F84 to a 16F87x chip, you have to concern yourself with the RP1 status bit as well as the RP0 bit when selecting banks. To be correct, use bcf STATUS, RP1 and bsf STATUS, RP0 for bank 1. It could trick you up, especially since some files can be accessed through banks 0 and 2, and 1 and 3. Unless you know from where you're coming in your code, you should try to set both bank bits to what you really need, not just the RP0 bit. --Andrew _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> PORTE will be in ANALOG mode. > > Change the ADCON1 register to make it work in digital mode. > > bsf STATUS,RP0 > movlw 6h ; all analog pins = digital > movwf ADCCON1 > bcf STATUS,RP0 > > > Make sure the unused pins on the other ports are set as outputs. >Tony Hi, The code is now changed (as above) all unused pins were set as output and i made sure i was refering to the right page: bcf STATUS, RP1 bsf STATUS, RP0 ---code--- There was a slight change, there are some characters (all the same and unreadable) at the display now when turning on. Maybe somone would take a look at the full code (it's short). http://aart.myip.org/test/ the 84 code is working and the 877 aint, i'm using a bootloader these are the first few lines. Thanks a lot, Aart. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Aart wrote: > > > PORTE will be in ANALOG mode. > > > > Change the ADCON1 register to make it work in digital mode. > > > > bsf STATUS,RP0 > > movlw 6h ; all analog pins = digital > > movwf ADCCON1 > > bcf STATUS,RP0 > > > > > > Make sure the unused pins on the other ports are set as outputs. > >Tony Try adding this... movlw B'00000000' ; RA0-5 = outputs movwf TRISA movlw B'00000000' ; RB0-7 = outputs movwf TRISB movlw B'00000000' ; RC0-7 = outputs movwf TRISC -- Best regards Tony mICros http://www.bubblesoftonline.com .....salesKILLspam@spam@picnpoke.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

Aart wrote: > There was a slight change, there are some characters (all the same and > unreadable) at the display now when turning on. Maybe somone would take a > look at the full code (it's short). OutMessage: movwf FSR ; Point at first letter OutLoop: movf FSR, w ; Get pointer into W incf FSR, f ; Set up for next letter call shomsg ; Get character to output iorlw 0 ; At the End of the Message? btfsc STATUS, Z ; Skip if not at end return ; Yes - Equal to Zero call SendCHAR ; Output the ASCII Character goto OutLoop ; Get the next character I would change the FSR references to "Temp1", or define a new RAM location like "CharIndex". Eg OutMessage: movwf CharIndex OuLoop: movf CharIndex, w ; Get pointer into W incf CharIndex, f ; Set up for next letter etc... etc... Although the FSR is primarily intended for indirect addressing, it can be used in the way presented, but it is best to use a GP RAM location instead. -- Best regards Tony mICros http://www.bubblesoftonline.com .....salesKILLspam.....picnpoke.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

----- Original Message ----- From: "Tony Nixon" <Tony.Nixonspam_OUTENG.MONASH.EDU.AU> To: <@spam@PICLISTKILLspamMITVMA.MIT.EDU> Sent: Monday, April 30, 2001 6:10 AM Subject: Re: [PIC]: LCD From 16F84 to 16F877 {Quote hidden}> Aart wrote: > > > > > PORTE will be in ANALOG mode. > > > > > > Change the ADCON1 register to make it work in digital mode. > > > > > > bsf STATUS,RP0 > > > movlw 6h ; all analog pins = digital > > > movwf ADCCON1 > > > bcf STATUS,RP0 > > > > > > > > > Make sure the unused pins on the other ports are set as outputs. > > >Tony > > Try adding this... > > > movlw B'00000000' ; RA0-5 = outputs > movwf TRISA > movlw B'00000000' ; RB0-7 = outputs > movwf TRISB > movlw B'00000000' ; RC0-7 = outputs > movwf TRISC > > -- > Best regards > > Tony > Done! No respons at all, even RA,0 won't change for half a sec. Can't find out what's wrong. Full code at http://aart.myip.org/test/ . I'm using a boot loader but that seems to work fine (with the test program, in C) then there's happening something, the test program sends a string and echo's characters at 19.200 . So the circuit seems to function okay. All lines are okay double checked it 5 times. HELP!! -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email KILLspamlistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

Aart, You were using a 4Mhz Xtal on the '84, and you also using a 4Mhz Xtal on the'877, if not you might want to check the delay routines for the LCD init are correct. Here is a snippit of code I use to give 100us delay LCD_D1 equ 0x30 LCD_D2 equ 0x31 #DEFINE LCD_xtal 0xA5 ;This should divide the clock to be 100us LCD_delay MOVWF LCD_D1 LCD_delay1 MOVLW LCD_xtal MOVWF LCD_D2 LCD_delay2 DECFSZ LCD_D2,F GOTO LCD_delay2 DECFSZ LCD_D1,F GOTO LCD_delay1 RETURN My init code is like this :- LCD_init LCD_delaym 150 ;Delay 15ms LCD_nibble LCD_4_init ;First Init Byte LCD_delaym 41 ;Delay 4.1ms LCD_nibble LCD_4_init ;Second Init Byte LCD_delaym 1 ;Delay 100us LCD_nibble LCD_4_init ;Third Init Byte LCD_delaym 41 ;Delay 4.1ms LCD_nibble LCD_4_mode_n ;Set 4 bit interface, busy flag now readable, from this point on use busy flag on not time delays LCD_command LCD_4_2_5x8 ;Select 2 line 5X8 4 bit mode LCD_command LCD_disp ;Display off Command LCD_command LCD_disp | LCD_d_on ;Display on, Cursor off LCD_command LCD_i_right ;Increment Cursor, No Scroll LCD_command LCD_clear ;Clear the display RETURN I include the LCD_init not for use as you have on that works anyway, but just to show the timings I use with LCD_delaym which is just a macro to move the litral to W and call LCD_delay. LCD_delaym macro argv MOVLW argv CALL LCD_delay endm I can let you have the full source if you want it, just ask. Regards Ben Please respond to pic microcontroller discussion list <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> To: spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU cc: (bcc: Ben SUFFOLK/EN/HTLUK) Subject: Re: [PIC]: LCD From 16F84 to 16F877 {Quote hidden}> PORTE will be in ANALOG mode. > > Change the ADCON1 register to make it work in digital mode. > > bsf STATUS,RP0 > movlw 6h ; all analog pins = digital > movwf ADCCON1 > bcf STATUS,RP0 > > > Make sure the unused pins on the other ports are set as outputs. >Tony Hi, The code is now changed (as above) all unused pins were set as output and i made sure i was refering to the right page: bcf STATUS, RP1 bsf STATUS, RP0 ---code--- There was a slight change, there are some characters (all the same and unreadable) at the display now when turning on. Maybe somone would take a look at the full code (it's short). http://aart.myip.org/test/ the 84 code is working and the 877 aint, i'm using a bootloader these are the first few lines. Thanks a lot, Aart. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. - att1.eml ******************************************************************************* Important. This E-mail is intended for the above named person and may be confidential and/or legally privileged. If this has come to you in error you must take no action based on it, nor must you copy or show it to anyone; please inform the sender immediately. ******************************************************************************* -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email TakeThisOuTlistservEraseMEspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

> Not necessary anymore.. IT WORKS! i made a mistake with the CBLOCK, didn't > change the variable "CBLOCK 0Ch" to "CBLOCK 20h" which is necessary > for the '877. Yet another reason for using relocatable mode and the RES directive. Too bad you can't go back and spend the time wasted on this bug to learn about relocatable mode instead. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, olinEraseME.....embedinc.com, http://www.embedinc.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservmitvma.mit.edu with SET PICList DIGEST in the body

I've built a couple of project using the 16F84, using an ancient programmer designed by Steve Marchant driven from a PC parallel port; I have the PC source for the programmer. It is very similar to the programmer described in the Microchip documentation, as I recall - it has been a couple of years since I have "PICed" I now would like to play around with the newer PICs, such as the 16F877. Question 1: is the physical programming of the new units the same as the F84 (in terms of voltages and timing)?. Question 2: Are there different registers etc that have to be set up compared to the F84 (during programming)? I have the data sheets for both products, but if someone out there has gone through this type of thing already, I'd appreciate any guidance. I'm not a large user of PICs, so buying a commercial programmer doesn't make economic sense. Thanks in advance Larry Larry Bradley Orleans (Ottawa), Ontario, CANADA -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservEraseMEEraseMEmitvma.mit.edu with SET PICList DIGEST in the body

Larry Bradley wrote: > > Question 1: is the physical programming of the new units the same as the > F84 (in terms of voltages and timing)?. Yes. The actual programming time is shortened, but that is internal to the PIC. > Question 2: Are there different registers etc that have to be set up > compared to the F84 (during programming)? Nope. The only diference, will be ROM/EEPROM size. Also, take note of the LVP pin, RB3. Keep it LOW while programming. -- Best regards Tony mICros http://www.bubblesoftonline.com RemoveMEsalesspam_OUTKILLspambubblesoftonline.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body

But LVP _is_ enabled in the config on a brand new part. Bob Amemrman RAm Systems ----- Original Message ----- From: "Peter Onion" <KILLspamponionspamBeGoneSRD.BT.CO.UK> To: <EraseMEPICLISTEraseMEMITVMA.MIT.EDU> Sent: Thursday, March 07, 2002 3:16 AM Subject: Re: From 16F84 to 16F877 > Somewhere in the middle of a load of html you said > > "I have found keeping the LVP pin low during high voltage programming > has eradicated programming errors I had been having if I left it floating." {Quote hidden}> > I've built my own "high voltage" programmer which doesn't do anything with > RB3 and not had any problems with errors at all. > > I wouldn't expect the state of RB3 to have any importance if LVP isn't > enabled in the config word. > > YMMV > > Peter. > > -- > http://www.piclist.com hint: To leave the PICList > @spam@piclist-unsubscribe-request@spam@spam_OUTmitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList spamBeGonepiclist-unsubscribe-requestKILLspammitvma.mit.edu

>> The only diference, will be ROM/EEPROM size. >> Also, take note of the LVP pin, RB3. Keep it LOW while programming. >I don't believe RB3 needs to be controled if you are using >traditional "high voltage" programing method. When the F87x flash parts first came out, a lot of programming problems were solved by grounding RB3 during high voltage programming. It's documented in the archives, and we certainly had that experience here. You are right - it shouldn't matter, but it did. I don't know if there was a problem with the chip that Microchip subsequently fixed, but we keep doing it whenever we use those parts. -- http://www.piclist.com hint: To leave the PICList TakeThisOuTpiclist-unsubscribe-request.....TakeThisOuTmitvma.mit.edu

On Thu, Mar 07, 2002 at 10:44:44AM -0000, Peter Onion wrote: > On 06-Mar-02 Tony Nixon wrote: > > > > The only diference, will be ROM/EEPROM size. > > > > Also, take note of the LVP pin, RB3. Keep it LOW while programming. > > I don't believe RB3 needs to be controled if you are using > traditional "high voltage" programing method. There has been at least one errata sheet published by Microchip that indicates that on some silicon revisions that a floating LVP pin can cause the chip to screw up going into programming mode, even when programming in HVP mode. It's always best to ground RB3/LVP when programming. > > If you are using "low voltage" programing then of course RB3 must be controled Of course. BAJ -- http://www.piclist.com hint: To leave the PICList TakeThisOuTpiclist-unsubscribe-requestKILLspamspammitvma.mit.edu

What is the different between High voltage Programming and LVP? Why do we want LVP or HVP? Thomas {Quote hidden}>From: Peter Onion <.....ponionRemoveMESRD.BT.CO.UK> >Reply-To: pic microcontroller discussion list <RemoveMEPICLISTspamBeGoneMITVMA.MIT.EDU> >To: spamBeGonePICLIST@spam@spam_OUTMITVMA.MIT.EDU >Subject: Re: From 16F84 to 16F877 >Date: Thu, 7 Mar 2002 11:16:57 -0000 > >Somewhere in the middle of a load of html you said > >"I have found keeping the LVP pin low during high voltage programming >has eradicated programming errors I had been having if I left it floating." > >I've built my own "high voltage" programmer which doesn't do anything with >RB3 and not had any problems with errors at all. > >I wouldn't expect the state of RB3 to have any importance if LVP isn't >enabled in the config word. > >YMMV > >Peter. > >-- >http://www.piclist.com hint: To leave the PICList >TakeThisOuTpiclist-unsubscribe-requestspammitvma.mit.edu > > _________________________________________________________________ Join the world s largest e-mail service with MSN Hotmail. http://www.hotmail.com -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestEraseMEmitvma.mit.edu

On Thu, Mar 07, 2002 at 09:04:27PM +0000, Thomas N wrote: > What is the different between High voltage Programming and LVP? HVP uses a nominal 13V signal on the MCLR pin to indicate that the PIC should go into programming mode. LVP uses a separate dedicated I/O (RB3 onthe 16F87X series, RB4 on the 16F62X series) to indicate to the PIC when to go into programming mode. The HVP/LVP mode is controlled by the LVP config bit in the config word. Note that the LVP bit cannot be reprogrammed in LVP mode. Note that HVP is just an indicator signal for all flash parts. All of the flash chips have an internal high voltage generator for actually programming the flash cells. > Why do we want LVP or HVP? Each has pros and cons. The primary question is the cost of an I/O pin vs. having to dedicate a programmable high voltage source in the programmer which makes it more complicated to design. In broad strokes HVP is probably better for the professional PIC user. LVP is great for the hobbiest because you can get started cheaply and quickly. For example my Trivial LVP programmer (http://www.finitesite.com/d3jsys) only consists of two parts, cables, and a 5V power source which is easily obtainable from the programmer host. Changing to HVP would require at minimum the high voltage supply and a transistor switch. However LVP has its issues too. First and foremost is that an I/O pin is permanently unavailable. I've been using 16F877's recently and I haven't missed it too much. The next annoying thing is that since all of the midrange PIC's pins on the edges of ports had already been allocated for special functions, they had to pick a pin that's in the middle of a port (RB3 or RB4) which breaks up a perfectly good 8 bit I/O port. I've learned to live with it. That's the scoop. Hope it helps, BAJ -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestEraseMEspam_OUTmitvma.mit.edu

> I don't believe RB3 needs to be controled if you are using > traditional "high voltage" programing method. > > If you are using "low voltage" programing then of course RB3 must be controled Oh oh, not again! At the very least there are versions of the various new flash chips that DO require that LVP is low *even when using HVP*. So just do it (pull LVP low) and don't spend time solving strange programming problems... Wouter van Ooijen -- Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler, Wisp programmer, WLoader bootloader, PICs kopen -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics