Introduction - Segger J-Link User Manual

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6.1

Introduction

The J-Link DLL comes with a lot of flash loaders that allow direct programming of
internal flash memory for popular microcontrollers. Moreover, the J-Link DLL also
allows programming of CFI-compliant external NOR flash memory. The flash down-
load feature of the J-Link DLL does not require an extra license and can be used free
of charge.
Why should I use the J-Link flash download feature?
Being able to download code directly into flash from the debugger or integrated IDE
significantly shortens the turn-around times when testing software. The flash down-
load feature of J-Link is very efficient and allows fast flash programming. For
example, if a debugger splits the download image into several pieces, the flash
download software will collect the individual parts and perform the actual flash pro-
gramming right before program execution. This avoids repeated flash programming. .
Moreover, the J-Link flash loaders make flash behave like RAM. This means that the
debugger only needs to select the correct device which enables the J-Link DLL to
automatically activate the correct flash loader if the debugger writes to a specific
memory address.
This also makes it very easy for debugger vendors to make use of the flash download
feature because almost no extra work is necessary on the debugger side since the
debugger does not have to differ between memory writes to RAM and memory writes
to flash.
J-Link / J-Trace (UM08001)
CHAPTER 6
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Flash download