X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/141f24b4a13144a49fe21f7352b0e9d34962e2dd..5ba628d10b54d58d445896290ba9799bd76a73b3:/Bootloaders/Printer/BootloaderPrinter.txt
diff --git a/Bootloaders/Printer/BootloaderPrinter.txt b/Bootloaders/Printer/BootloaderPrinter.txt
index 71e9b2871..d9aa79686 100644
--- a/Bootloaders/Printer/BootloaderPrinter.txt
+++ b/Bootloaders/Printer/BootloaderPrinter.txt
@@ -54,6 +54,30 @@
* When the bootloader is running, the board's LED(s) will flash at regular intervals to distinguish the
* bootloader from the normal user application.
*
+ * \section Sec_Running Running the Bootloader
+ *
+ * On the USB AVR8 devices, setting the \c HWBE device fuse will cause the bootloader to run if the \c HWB pin of
+ * the AVR is grounded when the device is reset.
+ *
+ * The are two behaviours of this bootloader, depending on the device's fuses:
+ *
+ * If the device's BOOTRST fuse is set, the bootloader will run any time the system is reset from
+ * the external reset pin, unless no valid user application has been loaded. To initiate the bootloader, the
+ * device's external reset pin should be grounded momentarily.
+ *
+ * If the device's BOOTRST fuse is not set, the bootloader will run only if initiated via a software
+ * jump, or if the \c HWB pin was low during the last device reset (if the \c HWBE fuse is set).
+ *
+ * For board specific exceptions to the above, see below.
+ *
+ * \subsection SSec_XPLAIN Atmel Xplain Board
+ * Ground the USB AVR JTAG's \c TCK pin to ground when powering on the board to start the bootloader. This assumes the
+ * \c HWBE fuse is cleared and the \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
+ *
+ * \subsection SSec_Leonardo Arduino Leonardo Board
+ * Ground \c IO13 when powering the board to start the bootloader. This assumes the \c HWBE fuse is cleared and the
+ * \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
+ *
* \section Sec_Installation Driver Installation
*
* This bootloader uses the Generic Text-Only printer drivers inbuilt into all modern operating systems, thus no
@@ -163,12 +187,6 @@
* are unable to handle true plain-text printing. For best results, the low
* level \c lpr command should be used to print new firmware to the bootloader.
*
- * \par After loading an application, it is not run automatically on startup.
- * Some USB AVR boards ship with the BOOTRST fuse set, causing the bootloader
- * to run automatically when the device is reset. In most cases, the BOOTRST
- * fuse should be disabled and the HWBE fuse used instead to run the bootloader
- * when needed.
- *
* \section Sec_Options Project Options
*
* The following defines can be found in this demo, which can control the demo behaviour when defined, or changed in value.