Post by thread:[PIC]: Help with USART on 16F627.

Hey all, I've got some modem routines working on the F627 however they are not making use of the USART, so I thought I'd be more efficent and get the modem working with USART. However after many hours going through the datasheets and Tom McGahee's USART program I still can't get it up and running. I'm trying to avoid using interrupts if possible and I'm trying just to get TX working for now. Here's my code hope someone can help, Thanks. If I have both TXD and RXD set as outputs the RXD light will flash when I start my write routine by the TXD won't work. If RXD is an input nothing. The following code sets the port up. MOVLW d'25' movwf SPBRG BCF TXSTA, SYNC BCF RCSTA, SPEN BSF TXSTA, CSRC BSF TXSTA, TXEN movlw 0 movwf TXREG My TX routine is: TX_MODEM movf dat_buf, w movwf TXREG ;wait_for_tx_to_end ; If I put this loop in it won't exit ;BTFSS TXSTA, TRMT ; The routine, so I put the delay in ;goto wait_for_tx_to_end movlw .5 CALL DELAY_N_MS RETURN Thanks for an assistance in advance, Aaron -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Are your bank bits set correctly? For example, you list: BCF TXSTA, SYNC BCF RCSTA, SPEN But TXSTA is in bank1, and RCSTA is in bank0. Thus, you would have to do the following: BCF STATUS, RP1 BSF STATUS, RP0 BCF TXSTA, SYNC BCF STATUS, RP1 BCF STATUS, RP0 BCF RCSTA, SPEN For the complete 16F627 memory map (keep this handy while programming!), see page 14 of the PIC16F62X datasheet. Jen -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

How about the fact that TXREG is in bank 0 and TXSTA is in bank 1. I see no bank switches in there. Same thing with spbrg (also in bank 1). Harold On Thu, 11 Jul 2002 11:57:19 -0400 "A.J. Tufgar" <spam_OUTtufgarajTakeThisOuTMUSS.CIS.MCMASTER.CA> writes: {Quote hidden}> Hey all, > I've got some modem routines working on the F627 however they > are not making use of the USART, so I thought I'd be more efficent > and > get the modem working with USART. However after many hours going > through the datasheets and Tom McGahee's USART program I still can't > get > it up and running. I'm trying to avoid using interrupts if possible > and > I'm trying just to get TX working for now. Here's my code hope > someone > can help, Thanks. > If I have both TXD and RXD set as outputs the RXD light will flash > when > I start my write routine by the TXD won't work. If RXD is an input > nothing. > The following code sets the port up. > MOVLW d'25' > movwf SPBRG > BCF TXSTA, SYNC > BCF RCSTA, SPEN > BSF TXSTA, CSRC > BSF TXSTA, TXEN > movlw 0 > movwf TXREG > > My TX routine is: > TX_MODEM > movf dat_buf, w > movwf TXREG > ;wait_for_tx_to_end ; If I put this loop in it won't > exit > ;BTFSS TXSTA, TRMT ; The routine, so I put the delay > in > ;goto wait_for_tx_to_end > movlw .5 > CALL DELAY_N_MS > RETURN > > > Thanks for an assistance in advance, > Aaron > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com Reach broadcasters, engineers, manufacturers, compliance labs, and attorneys. Advertise at http://www.hallikainen.com/FccRules/ . ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: dl.http://www.juno.com/get/web/. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> I've got some modem routines working on the F627 however they > are not making use of the USART, so I thought I'd be more efficent and > get the modem working with USART. However after many hours going > through the datasheets and Tom McGahee's USART program I still can't get > it up and running. I'm trying to avoid using interrupts if possible and > I'm trying just to get TX working for now. Here's my code hope someone > can help, Thanks. > If I have both TXD and RXD set as outputs That's definitely a problem. Both TRIS bits must be set for correct UART operation. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> Are your bank bits set correctly? > > For example, you list: > > BCF TXSTA, SYNC > BCF RCSTA, SPEN > > But TXSTA is in bank1, and RCSTA is in bank0. > > Thus, you would have to do the following: > BCF STATUS, RP1 > BSF STATUS, RP0 > BCF TXSTA, SYNC > > BCF STATUS, RP1 > BCF STATUS, RP0 > BCF RCSTA, SPEN > > For the complete 16F627 memory map (keep this handy while programming!), see > page 14 of the PIC16F62X datasheet. It's good to keep this handy, but even better to let the assembler generate the bank switching instructions for you. See my DBANKIF and related macros in STD.INS.ASPIC at http://www.embedinc.com/pic. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads