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