Tiny Bootloader
in [Embedded]
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From: Diogo G. Casado (a.k.a dIIo) on 30 Aug 2006 07:42 JohnT wrote: > If I don't put a GOTO in first four instructions it does indeed warn me > that there isn't a GOTO instruction. I also understand how the program > is suppose to work in the PIC. What I don't know and the site doesn't > tell you is what the download program does to your original code. > > Yes I have downloaded the example code as it that is is the program I'm > trying to get working. > > Neil wrote: > > CLIPPED > > JohnT wrote: > > > How do I post my code, I can't see of a way to upload a file. The > > > start of my code is as follows though. > > > > > > ORG 0x00 ; Start of the program > > > CLRF STATUS > > > MOVLW 0x00 > > > MOVWF PCLATH > > > GOTO INIT > > > > > > > > > ORG 0x04 ; Interrupt address > > > GOTO INT_HAND > > > > > > All I'm doing after it goes to the INIT routine is set all the outputs > > > on for PortA and B. I've simulated this and it works fine. > > > > > > John > > > > > the instructions show: > > > > > > org 0 > > ;clrf STATUS > > clrf PCLATH > > goto Main > > > > or > > > > org 0 > > ;clrf STATUS > > pagesel Main > > goto Main > > > > The web site says the PC Side will give a warning if the GOTO is wrong. > > > > Did you try to send his sample? JohnT, Strange... take a look at bootloader code on tinybld16F.asm: ORG first_address nop nop nop nop org first_address+4 IntrareBootloader And if you look deeper: way_to_exit ;exit in all other cases; must be BANK0/1 ;BANK0_ bcf RCSTA, SPEN ; deactivate UART goto first_address first_address is: #define first_address max_flash-100 ; 100 word in size So, what it does is: Loop forever into first_address while not receiving the 0xC1 char. In this case, you will need to put something like this in the end of your program: org max_flash-100 ; You will need to get max_flash value from boot loader includes. clrf PCLATH pagesel MyStart goto MyStart And in the start, don't use an org 0x00. I think that you need only setup the interrupt vector and after it continue with you program. ex: org 0x04 goto INT_HAND MyStart: LALALALA INT_HAND: LALLALAA org max_flash-100 ; You will need to get max_flash value from boot loader includes. clrf PCLATH pagesel MyStart goto MyStart Maybe you can use some #ifdefs using a def like #define USE_LOADER or something, in order to compile with or withou initialization... #ifndef USE_LOADER org 0x00 clrf STATUS movlw 0 movwf PCLATH goto MyStart #endif I don't why examples don't consider this, maybe some mismatch docs release... :) Hope it helps. - Diogo.
From: JohnT on 30 Aug 2006 13:06 I've looked through the bootloader and my interpretation is as follows :- 1. PIC Starts 2. Jumps to (Max_Memory - 100) 3. Waits a period of time for 'C1' to be received. 4a. If 'C1' is receieved then continue to rewrite the program that it is being sent. 4b If no 'C1' is received then exit the bootloader. 5 Jump to the start of the bootloader where the four 'nop' commands should have been replaced with the 'Goto' command that is at the start of my program. 6 It should find my 'Goto' command and then execute my program. I believe that the download program that you get off the site looks at the start of the user program. Finds this 'Goto' command and relocates it in memory to the start of the bootloader. I think this is where it is failing but I don't have the source code for the download program to verify this. Thanks
From: Stef Mientki on 30 Aug 2006 13:23
JohnT wrote: > I've looked through the bootloader and my interpretation is as follows > :- > > 1. PIC Starts > 2. Jumps to (Max_Memory - 100) > 3. Waits a period of time for 'C1' to be received. > 4a. If 'C1' is receieved then continue to rewrite the program that it > is being sent. > 4b If no 'C1' is received then exit the bootloader. > 5 Jump to the start of the bootloader where the four 'nop' commands > should have been replaced with the 'Goto' command that is at the start > of my program. > 6 It should find my 'Goto' command and then execute my program. > > > I believe that the download program that you get off the site looks at > the start of the user program. Finds this 'Goto' command and relocates > it in memory to the start of the bootloader. I think this is where it > is failing but I don't have the source code for the download program to > verify this. if you mean the UPLOAD program, here is the first part: <Pascal> const //bootloader types TINY =0; TOLMIE =1; TINY_IDENT = $C1; TINY_IDACK = ord('K'); function TForm_bootloader.TINY_Identify:boolean; (******************************************************************************* *******************************************************************************) begin with Form_comm_usb do begin Flush_Communication(true,true); //great improvement for RS232 !! Transmit_Buffer[0]:=TINY_IDENT; Transmit_Count:=1; result:=Send_Data; //Error message if not ok if not(result) then memo_uploader.lines.add('Transmit Error = '+inttostr(Transmit_Result)+' / '+inttostr(Transmit_Count)); end; end; function TForm_bootloader.TINY_Acknowledge:boolean; (******************************************************************************* *******************************************************************************) var received_byte :byte; starttime :cardinal; begin starttime:=gettickcount; repeat result:= Form_comm_usb.read_byte(TINY_PIC_type); application.processmessages; until result or (gettickcount-starttime>200); if not(result) then exit; starttime:=gettickcount; repeat result:= Form_comm_usb.read_byte(received_byte) and (received_byte=TINY_IDACK); application.processmessages; until result or (gettickcount-starttime>200); end; //main program reset_PIC; //try to he ping the PIC Ping_Count:=0; Uploading_Canceled:=false; repeat if not(TINY_IDENTIFY) then exit; Update_Ping_Count; if Uploading_Canceled then exit; application.ProcessMessages; until TINY_ACKNOWLEDGE; </Pascal> > > Thanks > |