A J-LINK uses SWDIO and SWCLK, with GND connected to the microcontroller FS32K144UAT0VLLT.
The program download circuit uses 5V for both VCC and the microcontroller.
- The RST pin has a triangular wave: f=1.8KHZ, 2.6Vp-p triangular wave:
3. When entering "unlock" in J-Link, Kinetis displays an error and cannot connect:
IV. The J-Link connection to the microcontroller's 97 pin PTA5 (*JTAG_TRST/*RESET) via the RST reset pin is successful, and decryption is successful. Does this mean decryption was successful?
5. When connecting the circuit board using Keil uVision5, the microcontroller cannot be connected without using RST; RST is required for connection.
And the triangular wave on the reset pin is still present, as shown in the following figure:
Question for NXP instructors:
This circuit board (using the FS32K144UAT0VLLT microcontroller) previously worked fine when only SWDIO, SWCLK, and GND were connected, allowing for normal program downloads. Why is it that this time, program downloads only occur after connecting RST? What could be the reason? Thank you!
Hi
Without RESET_b connected, J-Link cannot control the reset timing of the S32K1; intermittent connection failures may occur if the user program, watchdog timer, low-power mode, or pin multiplexing affects the debug port.
Because there is no code in the Flash (e.g., in a new chip, the Flash is empty), the MCU will continuously and periodically reset due to a core lockup. Furthermore, due to the external RC circuit, the square wave becomes a triangular wave.
Once you download a new, working program, the RESET_b pin will return to a high level.
Best Regards,
Robin
Dear teachers:
Sorry, the illustrations for the question I posted yesterday were not properly matched, making it very messy and unclear. I'm reposting it today, and I hope all the teachers can provide explanations as soon as possible!
When using the SW connection, the RST pin of the FS32K144UAT0VLLT still shows a triangular wave after unlocking. Without connecting the RST pin, the host computer cannot connect to the microcontroller.
A JLINK uses SWDIO and SWCLK, with GND connected to the microcontroller FS32K144UAT0VLLT.
The program download circuit uses 5V for both VCC and the microcontroller.
2. The RST pin shows a triangular wave: f=1.8KHZ, 2.6Vp-p triangular wave:
3. When entering "unlock" in J-Link, Kinetis displays an error and cannot connect:
4. Add the RST reset pin to the J-Link and connect it to the microcontroller's 97 pin PTA5 (*JTAG_TRST/*RESET). Connection successful, decryption successful.
5. When using Keil uVision5 to connect the circuit board, you cannot connect the microcontroller without using RST; you can only connect the microcontroller by using RST.
And the triangular wave on the reset pin is still present, as shown in the following figure:
Teacher: The above text is miswritten. Please see the Word document below; it's the same issue. Thank you!