stm32f405 minimal wiring

[Angelo1]

Posted on March 11, 2014 at 15:19

Dear,

i was trying to program stm32f405 through openpcd and a dcl5 parallel cable / interface that worked fine for other cortex cpu's. Until now i can't program successfully the device, so i am wandering what are the minimal connections needed: I connected: All VSS All VDD (+3.3) AS Jtag i connected only: JTCK -> pin 76 JTDI -> pin 77 JTDO -> pin 89 JTMS -> pin 72 VDDA and VREF+ are connected to +3.3 connected 2 x 2,2u caps. NRST is held high through RC circuit. then i dindn't connected any external crystal, all the rest is left unconnected. Am i missing something important for a simple first flash programming  ? many thanks angelo #wandering-!=-wondering

[Tesla DeLorean]

Posted on March 11, 2014 at 15:33

Am i missing something important for a simple first flash programming  ?

Not really, I'd perhaps had wired NRST and NJTRST to the JTAG If the debugger can't see the JTAG chain, then take a close look at how you have it wired up. Common GND. Try a more industrial/commercial JTAG pod Check for the ~1.2V on the VCAPx pins. Check part orientation. With BOOT0 pulled high, check USART1/USART3 connectivity with Flash Demonstrator, or send 0x7F at 9600 8E1 and see if you get 0x79 response back.

[Angelo1]

Posted on March 13, 2014 at 18:45

solved, many thanks.

Was a problem of the small cable (10cm) from my parport dcl5 interface to the pcb. I removed the cable completely, and connect the interface directly with a male-female connector. Now, i still have sometime flash programming issues, so i moved down to 100Khz the speed and is much better, but still some error sometime. Should i put some pullup on the board ? From stm32 datasheet seems there are already pull-up / down embedded on the chip. Thanks Angelo