Post by thread:Learningssembly

Hello All. I have noticed that not many people are using PIC C.. so I have decided to teach myself assembly. I have a number of very quick, small questions. Here is the code I have come up with so far: ;============================================ list p=16f84 TMR0 EQU 0x01 OREG EQU 0x81 PORTA EQU 0x05 TRISA EQU 0x85 STATUS EQU 0x03 RP0 EQU 5 W EQU 0 ORG 0x000 BEGIN: BSF STATUS, RP0 ;Bank 1 MOVLW b'11011000' MOVWF OREG ;Setup Option Register MOVLW b'0000' MOVWF TRISA ;Make PORTA outputs LOOP: ;Do loop stuff in here. GOTO LOOP END ;============================================ When I compile this using MPLAB I get the following warnings: Message[302] C:\WINDOWS\DESKTOP\LED.ASM 14 : Register in operand not in bank 0. Ensure that bank bits are correct. Message[302] C:\WINDOWS\DESKTOP\LED.ASM 16 : Register in operand not in bank 0. Ensure that bank bits are correct. My code sets the option register to bank 1... so why would I get these warnings? also.. how do you deal with registers that are in both banks? (STATUS, INTCON, PCLATH,FSR) I just equated the STATUS register to the lowest HEX value (0x03) and my final small question is this... which way is better to set a variable, load a literal into W and then store it in "f" like I did in my code, or like the following: MOVF b'11011000',OREG Thanks for any and all help, sorry to be a pest.

<snip> > When I compile this using MPLAB I get the following warnings: > > Message[302] C:\WINDOWS\DESKTOP\LED.ASM 14 : Register in operand not in bank > 0. Ensure that bank bits are correct. > Message[302] C:\WINDOWS\DESKTOP\LED.ASM 16 : Register in operand not in bank > 0. Ensure that bank bits are correct. > > My code sets the option register to bank 1... so why would I get these > warnings? It's normal...the assembler just gives the warning anyway. There is a way to turn it off, you can most likely find it in the help/manual. (ot maybe the archives....) > also.. how do you deal with registers that are in both banks? (STATUS, > INTCON, PCLATH,FSR) I just equated the STATUS register to the lowest HEX > value (0x03) That's exactly what you do...there is an include file for each processor that has all the register definitions set up so you don't have to. These should be in the mplab directory. > and my final small question is this... which way is better to set a > variable, load a literal into W and then store it in "f" like I did in my > code, or like the following: > MOVF b'11011000',OREG The only(?) way to do it is to use the W method as you did in your code, the above instruction will not compile (as far as I know) it isn't a standard operation. Mplab may expand this into the two lines that would normally be used, but I'd just stick to the proper intraction to begin with > Thanks for any and all help, sorry to be a pest. No problem, Don

look at this it will kill you problem ----- Original Message ----- From: "Samuel Ace Winchenbach" <spam_OUTswinchenTakeThisOuTEECE.MAINE.EDU> To: <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> Sent: Tuesday, May 16, 2000 7:22 PM Subject: Learningssembly {Quote hidden}> Hello All. > > I have noticed that not many people are using PIC C.. so I have decided to > teach myself assembly. I have a number of very quick, small questions. > Here is the code I have come up with so far: > ;============================================ > list p=16f84 > TMR0 EQU 0x01 > OREG EQU 0x81 ->0x01 ; are in bank_1 > PORTA EQU 0x05 > TRISA EQU 0x85 ->0x05 ;are in bank_1 > STATUS EQU 0x03 > RP0 EQU 5 > W EQU 0 > > ORG 0x000 > BEGIN: > BSF STATUS, RP0 ;Bank 1 > MOVLW b'11011000' > MOVWF OREG ;Setup Option Register > MOVLW b'0000' ->00000 > MOVWF TRISA ;Make PORTA outputs > > > LOOP: ;Do loop stuff in here. > > GOTO LOOP > END > ;============================================ > When I compile this using MPLAB I get the following warnings: > > Message[302] C:\WINDOWS\DESKTOP\LED.ASM 14 : Register in operand not in bank > 0. Ensure that bank bits are correct. > Message[302] C:\WINDOWS\DESKTOP\LED.ASM 16 : Register in operand not in bank > 0. Ensure that bank bits are correct. > > My code sets the option register to bank 1... so why would I get these > warnings? > also.. how do you deal with registers that are in both banks? (STATUS, > INTCON, PCLATH,FSR) I just equated the STATUS register to the lowest HEX > value (0x03) > > and my final small question is this... which way is better to set a > variable, load a literal into W and then store it in "f" like I did in my > code, or like the following: > MOVF b'11011000',OREG > > Thanks for any and all help, sorry to be a pest. >

Sam.... Last question first: you cannot move one ram location to another, you must first move it to W and then from W to f. As I recall, you can ask the asemble to eliminate the "302" potential assembly error. I ignor it. It will not affect your code, just a warning. As I recall, you can access a register shown in the table as either bank 0 or bank 1 from either bank your code is executed in. I recommend the basic book by John Peatman, "Design with PIC Microcontrollers." You can order from the on-line bookstores. He's a prof at Georgia Tech. Good read, and reasonably quick. Phil Anderson. Good Luck! On Tuesday, May 16, 2000 12:22 PM, Samuel Ace Winchenbach [SMTP:swinchenKILLspamEECE.MAINE.EDU] wrote: > Hello All. > > I have noticed that not many people are using PIC C.. so I have decided to {Quote hidden}> teach myself assembly. I have a number of very quick, small questions. > Here is the code I have come up with so far: > ;============================================ > list p=16f84 > TMR0 EQU 0x01 > OREG EQU 0x81 > PORTA EQU 0x05 > TRISA EQU 0x85 > STATUS EQU 0x03 > RP0 EQU 5 > W EQU 0 > > ORG 0x000 > BEGIN: > BSF STATUS, RP0 ;Bank 1 > MOVLW b'11011000' > MOVWF OREG ;Setup Option Register > MOVLW b'0000' > MOVWF TRISA ;Make PORTA outputs > > > LOOP: ;Do loop stuff in here. > > GOTO LOOP > END > ;============================================ > When I compile this using MPLAB I get the following warnings: > > Message[302] C:\WINDOWS\DESKTOP\LED.ASM 14 : Register in operand not in bank > 0. Ensure that bank bits are correct. > Message[302] C:\WINDOWS\DESKTOP\LED.ASM 16 : Register in operand not in bank {Quote hidden}> 0. Ensure that bank bits are correct. > > My code sets the option register to bank 1... so why would I get these > warnings? > also.. how do you deal with registers that are in both banks? (STATUS, > INTCON, PCLATH,FSR) I just equated the STATUS register to the lowest HEX > value (0x03) > > and my final small question is this... which way is better to set a > variable, load a literal into W and then store it in "f" like I did in my > code, or like the following: > MOVF b'11011000',OREG > > Thanks for any and all help, sorry to be a pest.