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Custom Board Design with STM32L4 - Flash Programming and JTAG Questions

Question asked by Atilla Mete Turedi on Sep 28, 2017
Latest reply on Oct 4, 2017 by AvaTar

Dear Community,


I went through most of the application notes, the datasheet and the reference manual but since I am a hardware guy, I want to make sure that I understand things correctly before I start the design. I am consent with basic yes/no confirmations from people with experience.


1. I can program a bare metal MCU using the 10-pin JTAG connector alone.

2. I can use the IAR EWARM + Segger J-Link Pro combination for debug and flash programming.

3. I can set all JTAG pins (PA13, PA14, PA15, PB3 and PB4) to their alternate functions.

4. Each time the MCU is reset, even if JTAG was previously disabled by the application program, all JTAG pins are set back to JTAG functionality and JTAG is enabled.


I just want to make sure that, I can use JTAG and only JTAG for flash programming of the MCU and my application program can use all the pins used by JTAG as GPIOs. 


And more thing, this might sound dumb but none of the alternate functions are actually named "GPIO" in the datasheet. How do I set them as just basic GPIO and not one of the alternate functions?


Best Regards,