Posted on February 07, 2015 at 11:43Hi,
I have made my own pcb design using STM32F407VGT6 in LQFP100 package.I used the stm32f4 launch board schematic.I pulled down the boot0 and boot1 pins using voltage divider (10k//510).I connected 15 100nf caps to vdd pins and 2.2 uF caps to Vcap pins , 100nf cap to nrst pin also used ld1117 3.3 v regulator with 22uF output capacitor.
At first pcb worked fine and I downloaded my code to flash using j-link edu.But after I pressed the reset button MCU failed to start-up so i tried to download my code again and i got this error log from keil.
* JLink Info: Found SWD-DP with ID 0x2BA01477
* JLink Info: Found SWD-DP with ID 0x2BA01477
* JLink Info: Found Cortex-M4 r0p1, Little endian.
* JLink Info: FPUnit: 6 code (BP) slots and 2 literal slots
* JLink Info: TPIU fitted.
* JLink Info: ETM fitted.
ROMTableAddr = 0xE00FF003
* JLink Info: SYSRESETREQ has confused core. Trying to reconnect and use VECTRESET.
* JLink Info: Found SWD-DP with ID 0x2BA01477
**JLink Warning: Failed to reset CPU. VECTRESET has confused core.
**JLink Warning: CPU did not halt after reset.
**JLink Warning: CPU could not be halted
* JLink Info: Core did not halt after reset, trying to disable WDT.
**JLink Warning: CPU did not halt after reset.
**JLink Warning: CPU could not be halted
**JLink Warning: Could not set S_RESET_ST
* JLink Info: Found SWD-DP with ID 0x2BA01477
* JLink Info: SYSRESETREQ has confused core. Trying to reconnect and use VECTRESET.
* JLink Info: Found SWD-DP with ID 0x2BA01477
**JLink Warning: Failed to reset CPU. VECTRESET has confused core.
**JLink Warning: CPU did not halt after reset.
**JLink Warning: CPU could not be halted
* JLink Info: Core did not halt after reset, trying to disable WDT.
**JLink Warning: CPU did not halt after reset.
**JLink Warning: CPU could not be halted
**JLink Warning: Could not set S_RESET_ST
***JLink Error: Error while identifying Cortex-M core.
**JLink Warning: CPU could not be halted
It seemed like j link can not reset the MCU so I tried to reset the MCU with pulling down the nrst pin with jumper and tried again but that did not work at all.Should I use a bigger capacitor or connect 1k resistor to nrst pin as shown in olimex pcb design.
