USB bootloading - Revision history

Gregory McGlynn at 13:04, 11 June 2009

2009-06-11T13:04:16Z

← Older revision		Revision as of 08:04, 11 June 2009
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			'''MPLAB/C18:'''
	With MPLAB/C18 the required code is a bit longer. So as not to clutter up this page, it's on a separate one: see [[Compiling for a bootloader in MPLAB]].		With MPLAB/C18 the required code is a bit longer. So as not to clutter up this page, it's on a separate one: see [[Compiling for a bootloader in MPLAB]].

	'''HID bootloader with MPLAB:'''
	<pre>//The following lengthy and involved incantation sets things up so that resets and interrupt
	//handling operate as they should, given the presence of the bootloader.
	//Omitting this incantation will make the code stop working.
	//If you are generating absolutely no interrupts, you can probably leave out just the stuff
	//referring to interrupts.
	//Comments are by Microchip.


	//On PIC18 devices, addresses 0x00, 0x08, and 0x18 are used for
	//the reset, high priority interrupt, and low priority interrupt
	//vectors. However, the current Microchip USB bootloader
	//examples are intended to occupy addresses 0x00-0x7FF or
	//0x00-0xFFF depending on which bootloader is used. Therefore,
	//the bootloader code remaps these vectors to new locations
	//as indicated below. This remapping is only necessary if you
	//wish to program the hex file generated from this project with
	//the USB bootloader.
	#define REMAPPED_RESET_VECTOR_ADDRESS 0x1100
	#define REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS 0x1108
	#define REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS 0x1118

	void YourHighPriorityISRCode();
	void YourLowPriorityISRCode();

	extern void _startup (void); // See c018i.c in your C18 compiler dir
	#pragma code REMAPPED_RESET_VECTOR = REMAPPED_RESET_VECTOR_ADDRESS
	void _reset (void)
	{
	_asm goto _startup _endasm
	}

	#pragma code REMAPPED_HIGH_INTERRUPT_VECTOR = REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS
	void Remapped_High_ISR (void)
	{
	_asm goto YourHighPriorityISRCode _endasm
	}
	#pragma code REMAPPED_LOW_INTERRUPT_VECTOR = REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS
	void Remapped_Low_ISR (void)
	{
	_asm goto YourLowPriorityISRCode _endasm
	}

	//If the output hex file is not programmed with
	//the bootloader, addresses 0x08 and 0x18 would end up programmed with 0xFFFF.
	//As a result, if an actual interrupt was enabled and occured, the PC would jump
	//to 0x08 (or 0x18) and would begin executing "0xFFFF" (unprogrammed space). This
	//executes as nop instructions, but the PC would eventually reach the REMAPPED_RESET_VECTOR_ADDRESS
	//(0x1000 or 0x800, depending upon bootloader), and would execute the "goto _startup". This
	//would effective reset the application.

	//To fix this situation, we should always deliberately place a
	//"goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS" at address 0x08, and a
	//"goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS" at address 0x18. When the output
	//hex file of this project is programmed with the bootloader, these sections do not
	//get bootloaded (as they overlap the bootloader space). If the output hex file is not
	//programmed using the bootloader, then the below goto instructions do get programmed,
	//and the hex file still works like normal. The below section is only required to fix this
	//scenario.
	#pragma code HIGH_INTERRUPT_VECTOR = 0x08
	void High_ISR (void)
	{
	_asm goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS _endasm
	}
	#pragma code LOW_INTERRUPT_VECTOR = 0x18
	void Low_ISR (void)
	{
	_asm goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS _endasm
	}

	#pragma code

	#pragma interrupt YourHighPriorityISRCode
	void YourHighPriorityISRCode()
	{
	//Check which interrupt flag caused the interrupt.
	//Service the interrupt
	//Clear the interrupt flag
	//Etc.
	} //This return will be a "retfie fast", since this is in a #pragma interrupt section

	#pragma interruptlow YourLowPriorityISRCode
	void YourLowPriorityISRCode()
	{
	//Check which interrupt flag caused the interrupt.
	//Service the interrupt
	//Clear the interrupt flag
	//Etc.
	} //This return will be a "retfie", since this is in a #pragma interruptlow section

	//End incantation</pre>

	Here's a shorter version of the same thing, stripped of most explanatory comments:
	<pre>#define REMAPPED_RESET_VECTOR_ADDRESS 0x1100
	#define REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS 0x1108
	#define REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS 0x1118

	void YourHighPriorityISRCode();
	void YourLowPriorityISRCode();

	extern void _startup (void); // See c018i.c in your C18 compiler dir
	#pragma code REMAPPED_RESET_VECTOR = REMAPPED_RESET_VECTOR_ADDRESS
	void _reset (void) { _asm goto _startup _endasm }

	#pragma code REMAPPED_HIGH_INTERRUPT_VECTOR = REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS
	void Remapped_High_ISR (void) { _asm goto YourHighPriorityISRCode _endasm }

	#pragma code REMAPPED_LOW_INTERRUPT_VECTOR = REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS
	void Remapped_Low_ISR (void) { _asm goto YourLowPriorityISRCode _endasm }

	#pragma code HIGH_INTERRUPT_VECTOR = 0x08
	void High_ISR (void) { _asm goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS _endasm }
	#pragma code LOW_INTERRUPT_VECTOR = 0x18
	void Low_ISR (void) { _asm goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS _endasm }

	#pragma code

	#pragma interrupt YourHighPriorityISRCode
	void YourHighPriorityISRCode() {
	//high priority interrupt code
	}

	#pragma interruptlow YourLowPriorityISRCode
	void YourLowPriorityISRCode() {
	//low priority interrupt code
	}</pre>


	If you wish to use the CDC bootloader with MPLAB source code, you only need to change three lines of the above, where the REMAPPED_VECTOR_ADDRESS constants are defined:

	<pre>#define REMAPPED_RESET_VECTOR_ADDRESS 0x800
	#define REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS 0x808
	#define REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS 0x818
	</pre>

	== See also ==		== See also ==

Gregory McGlynn at 12:46, 11 June 2009

2009-06-11T12:46:04Z

← Older revision		Revision as of 07:46, 11 June 2009
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	=== PIC software ===		=== PIC software ===

	You can download the PIC hex file here.		You can download the PIC hex file here: [[Media:HID_Bootloader_PIC18_Non_J.hex]].

	You can download the full MPLAB project for the PIC program here.		You can download the full MPLAB project for the PIC program here: [[Media:Mplab-usb-bootloader.zip]].

	=== PC software ===		=== PC software ===
Line 77:		Line 78:


	With MPLAB/C18 the required code is a bit longer:		With MPLAB/C18 the required code is a bit longer. So as not to clutter up this page, it's on a separate one: see [[Compiling for a bootloader in MPLAB]].

	'''HID bootloader with MPLAB:'''		'''HID bootloader with MPLAB:'''

Gregory McGlynn at 12:40, 11 June 2009

2009-06-11T12:40:36Z

← Older revision		Revision as of 07:40, 11 June 2009
Line 52:		Line 52:
	=== PC software ===		=== PC software ===

	You can download the PC program here. ~~It also~~ comes as part of the [[Microchip USB Framework]]. ~~When~~ the ~~program~~ is ~~running~~ it ~~should automatically detect when you attach~~ the ~~PIC~~ ~~(if~~ ~~the~~ ~~PIC~~ ~~has~~ ~~been~~ ~~properly~~ ~~programmed).~~ To ~~program~~ the ~~PIC click~~ ~~"Open Hex File~~," ~~and~~ ~~browse~~ ~~your~~ ~~compiled~~ ~~hex~~ ~~file.~~ ~~Then~~ ~~click~~ ~~"Program/Verify"~~ ~~and~~ ~~the~~ ~~bootloader~~ ~~should,~~ ~~after~~ a ~~few~~ ~~seconds,~~ ~~report~~ ~~that~~ it ~~has~~ ~~successfully~~ ~~erase, programmed, and verified~~ the ~~PIC.~~ ~~After~~ ~~that~~ ~~you~~ ~~can~~ ~~reset~~ ~~the~~ ~~PIC and it should run your program~~.		You can download the PC program here (it comes as part of the [[Microchip USB Framework]]): [[Media:HIDBootLoader.zip]]. Unzip the downloaded .zip file to get the HIDBootLoader.exe executable. Running this requires a sufficiently recent version of the .NET Framework, which you may not have if you are running XP or earlier versions of Windows. You can download a sufficiently recent version here (the install takes a while): [http://www.microsoft.com/downloads/details.aspx?FamilyId=333325FD-AE52-4E35-B531-508D977D32A6&displaylang=en .NET Framework download].

			When the program is running it should automatically detect when you attach the PIC (if the PIC has been properly programmed). To program the PIC click "Open Hex File," and browse your compiled hex file. Then click "Program/Verify" and the bootloader should, after a few seconds, report that it has successfully erase, programmed, and verified the PIC. After that you can reset the PIC and it should run your program.

	=== Required circuitry ===		=== Required circuitry ===

Gregory McGlynn at 14:40, 7 June 2009

2009-06-07T14:40:13Z

← Older revision		Revision as of 09:40, 7 June 2009
Line 179:		Line 179:
	extern void _startup (void); // See c018i.c in your C18 compiler dir		extern void _startup (void); // See c018i.c in your C18 compiler dir
	#pragma code REMAPPED_RESET_VECTOR = REMAPPED_RESET_VECTOR_ADDRESS		#pragma code REMAPPED_RESET_VECTOR = REMAPPED_RESET_VECTOR_ADDRESS
	void _reset (void)		void _reset (void) { _asm goto _startup _endasm }
	{
	_asm goto _startup _endasm
	}

	#pragma code REMAPPED_HIGH_INTERRUPT_VECTOR = REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS		#pragma code REMAPPED_HIGH_INTERRUPT_VECTOR = REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS
	void Remapped_High_ISR (void)		void Remapped_High_ISR (void) { _asm goto YourHighPriorityISRCode _endasm }

	{
	_asm goto YourHighPriorityISRCode _endasm
	}
	#pragma code REMAPPED_LOW_INTERRUPT_VECTOR = REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS		#pragma code REMAPPED_LOW_INTERRUPT_VECTOR = REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS
	void Remapped_Low_ISR (void)		void Remapped_Low_ISR (void) { _asm goto YourLowPriorityISRCode _endasm }
	{
	_asm goto YourLowPriorityISRCode _endasm
	}

	#pragma code HIGH_INTERRUPT_VECTOR = 0x08		#pragma code HIGH_INTERRUPT_VECTOR = 0x08
	void High_ISR (void)		void High_ISR (void) { _asm goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS _endasm }
	{
	_asm goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS _endasm
	}
	#pragma code LOW_INTERRUPT_VECTOR = 0x18		#pragma code LOW_INTERRUPT_VECTOR = 0x18
	void Low_ISR (void)		void Low_ISR (void) { _asm goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS _endasm }
	{
	_asm goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS _endasm
	}

	#pragma code		#pragma code

	#pragma interrupt YourHighPriorityISRCode		#pragma interrupt YourHighPriorityISRCode
	void YourHighPriorityISRCode()		void YourHighPriorityISRCode() {
	{
	//high priority interrupt code		//high priority interrupt code
	}		}

	#pragma interruptlow YourLowPriorityISRCode		#pragma interruptlow YourLowPriorityISRCode
	void YourLowPriorityISRCode()		void YourLowPriorityISRCode() {
	{
	//low priority interrupt code		//low priority interrupt code
	}</pre>		}</pre>

Gregory McGlynn: /* Compiling for a bootloader */

2009-06-07T14:36:48Z

Compiling for a bootloader

Show changes

Gregory McGlynn at 14:29, 7 June 2009

2009-06-07T14:29:29Z

@@ Line 1: / Line 1: @@
-'''This article assumes you are using Windows.'''
+'''This article assumes you are using Windows. The provided code is intended to be run on a [[PIC 18f4550|PIC18F4550 or 4553]] with a 20Mhz oscillator.'''
 Bootloading allows you to reprogram your PIC without the need for an expensive hardware programmer like an ICD.
@@ Line 11: / Line 11: @@
 == CDC Bootloader ==
@@ Line 28: / Line 25: @@
 === Required circuitry ===
-You need some sort of button or switch hooked up to pin RC2 so that it is normally high. If you reset the PIC and pin RC2 is high, the bootloader will run whatever program you've loaded onto it. But if RC2 is low, because you're pressing the button, the bootloader will run, allowing you to load a new program onto the PIC. You don't need to keep holding the button down, C2 just has to be low at the time the PIC resets. So whenever you want to put the PIC into bootloader mode, press and hold the reset button, then press your bootloading button, then release the reset button, then release the bootloading button. You can attach an LED to pin RC1 and the bootloader will flash it when it runs.
+You need some sort of button or switch hooked up to pin RC2 so that it is normally high. If you reset the PIC and pin RC2 is high, the bootloader will run whatever program you've loaded onto it. But if RC2 is low, because you're pressing the button, the bootloader will run, allowing you to load a new program onto the PIC. You don't need to keep holding the button down, C2 just has to be low at the time the PIC resets. So whenever you want to put the PIC into bootloader mode, press and hold the reset button, then press your bootloading button, then release the reset button, then release the bootloading button. You can attach an LED to pin RC1 and the bootloader will flash it when it runs. These pins can be easily changed in the bootloader source code.
 === Installing Drivers ===
 When you first connect the PIC to the PC and make the bootloader run, Windows will need to install a driver. Point it to "C:\MCHPFSUSB\Pc\MCHPUSB Driver\Release" and it will install the right driver. Now you're all set up.
 === Bootloading ===
@@ Line 48: / Line 39: @@
 * Click "Program Device" to load your program.
 * Reset your PIC and your program should run.
 == See also ==

Gregory McGlynn at 01:33, 7 June 2009

2009-06-07T01:33:03Z

← Older revision		Revision as of 20:33, 6 June 2009
Line 13:		Line 13:
	== USB Bootloading with the [[PIC 18f4553]] ==		== USB Bootloading with the [[PIC 18f4553]] ==
	USB bootloading is bootloading over a USB cable. To do this you need to be working with a PIC that talks USB, like an 18f4553. Then you need to have a bootloader on the PIC. The only way to put a bootloader in place is with a hardware programmer like an ICD, but you only need to do this once: afterwards, all you'll need is a regular USB cable. See [[USB communication with PC\|here]] for how to connect a USB cable to a PIC.		USB bootloading is bootloading over a USB cable. To do this you need to be working with a PIC that talks USB, like an 18f4553. Then you need to have a bootloader on the PIC. The only way to put a bootloader in place is with a hardware programmer like an ICD, but you only need to do this once: afterwards, all you'll need is a regular USB cable. See [[USB communication with PC\|here]] for how to connect a USB cable to a PIC.

			== HID Bootloader ==

			A HID (Human Interface Device) bootloader has the advantage that it doesn't require any driver installation on the programming computer. Once the bootloader is programmed onto the PIC and the PIC is plugged into the PC, your computer should be able to handle the rest of the setup automatically. A HID bootloader is supplied with the Microchip USB Framework. You can download the PC program here. You can download the PIC hex file here. You can download the full MPLAB project for the PIC program here. This is a slightly modified version of the original HID bootloader project from Microchip. The original project is designed to fit within the first 0x1000 bytes of program memory, but due to changes in the compiler will no longer compile into that space; the modified version goes int he first 0x1100 bytes.

			== CDC Bootloader ==

	=== Loading the bootloader ===		=== Loading the bootloader ===
	Here is a USB bootloader hex file that works for the 18f4553 with a 20Mhz oscillator: [[Image:FW_B_20.hex]]. It comes from http://www.schmalzhaus.com/UBW , where you can find the source it was built from, if you're interested.		Here is a USB bootloader hex file that works for the 18f4553 with a 20Mhz oscillator: [[Image:FW_B_20.hex]]. It comes from http://www.schmalzhaus.com/UBW , where you can find the source it was built from, if you're interested. The bootloader is a slightly modified version of one supplied by Microchip; the changes allow the compiled hex file to fit within the first 0x800 bytes program memory.
	To load this precompiled hex file onto the PIC using the CCS ICD, use the icd.exe program in the C:\Program Files\PICC directory. Now the bootloader is itself loaded.		To load this precompiled hex file onto the PIC using the CCS ICD, use the icd.exe program in the C:\Program Files\PICC directory. Now the bootloader is itself loaded.

Gregory McGlynn at 01:51, 27 April 2009

2009-04-27T01:51:20Z

← Older revision		Revision as of 20:51, 26 April 2009
Line 11:		Line 11:


	== USB Bootloading with the PIC 18f4553 ==		== USB Bootloading with the [[PIC 18f4553]] ==
	USB bootloading is bootloading over a USB cable. To do this you need to be working with a PIC that talks USB, like an 18f4553. Then you need to have a bootloader on the PIC. The only way to put a bootloader in place is with a hardware programmer like an ICD, but you only need to do this once: afterwards, all you'll need is a regular USB cable. See [[USB communication with PC\|here]] for how to connect a USB cable to a PIC.		USB bootloading is bootloading over a USB cable. To do this you need to be working with a PIC that talks USB, like an 18f4553. Then you need to have a bootloader on the PIC. The only way to put a bootloader in place is with a hardware programmer like an ICD, but you only need to do this once: afterwards, all you'll need is a regular USB cable. See [[USB communication with PC\|here]] for how to connect a USB cable to a PIC.

Kwang Sim: by Greg McGlynn

2009-04-21T16:59:54Z

by Greg McGlynn

← Older revision		Revision as of 11:59, 21 April 2009
Line 38:		Line 38:
	* Compile your program with the two lines mentioned above.		* Compile your program with the two lines mentioned above.
	* Fire up PDFSUSB.exe.		* Fire up PDFSUSB.exe.
	* Put your PIC into bootloading mode. You should now be able to select "~~PIC DEM~~ FS 0" from the PDFSUSB.exe drop-down list.		* Put your PIC into bootloading mode. You should now be able to select "PICDEM FS USB 0" from the PDFSUSB.exe drop-down list.
	* Click "Load Hex File" and go find the hex file that you created when you compiled your program.		* Click "Load Hex File" and go find the hex file that you created when you compiled your program.
	* Click "Program Device" to load your program.		* Click "Program Device" to load your program.

Kwang Sim: by Greg McGlynn

2009-04-21T16:55:46Z

by Greg McGlynn

← Older revision		Revision as of 11:55, 21 April 2009
Line 19:		Line 19:

	=== The PC software ===		=== The PC software ===
	There needs to be a program on the PC that sends your hex files to bootloader on the PIC. This bootloader uses a program from the Microchip USB Framework. You can download the framework installer [http://ww1.microchip.com/downloads/en/DeviceDoc/MCHPFSUSB_Setup_v1.3.exe here]. It will create some folders in the C:\ directory. The loader program is at ~~(some location)~~.		There needs to be a program on the PC that sends your hex files to bootloader on the PIC. This bootloader uses a program from the Microchip USB Framework. You can download the framework installer [http://ww1.microchip.com/downloads/en/DeviceDoc/MCHPFSUSB_Setup_v1.3.exe here]. It will create some folders in the C:\ directory. The loader program is at C:\MCHPFSUSB\Pc\Pdfsusb\PDFSUSB.exe.

	=== Required circuitry ===		=== Required circuitry ===
Line 25:		Line 25:

	=== Installing Drivers ===		=== Installing Drivers ===
	When you first connect the PIC to the PC and make the bootloader run, Windows will need to install a driver. Point it to ~~(some~~ ~~location)~~ and it will install the right driver. Now you're all set up.		When you first connect the PIC to the PC and make the bootloader run, Windows will need to install a driver. Point it to "C:\MCHPFSUSB\Pc\MCHPUSB Driver\Release" and it will install the right driver. Now you're all set up.

	=== Compiling for a bootloader ===		=== Compiling for a bootloader ===
Line 37:		Line 37:

	* Compile your program with the two lines mentioned above.		* Compile your program with the two lines mentioned above.
	* Fire up ~~(some location)~~.exe.		* Fire up PDFSUSB.exe.
	* Put your PIC into bootloading mode. You should now be able to select ~~(some~~ ~~string)~~ from the ~~(some string)~~.exe drop-down list.		* Put your PIC into bootloading mode. You should now be able to select "PIC DEM FS 0" from the PDFSUSB.exe drop-down list.
	* Click "Load Hex File" and go find the hex file that you created when you compiled your program.		* Click "Load Hex File" and go find the hex file that you created when you compiled your program.
	* Click "Program Device" to load your program.		* Click "Program Device" to load your program.