Problem with 32U4-AU

Other Hardware 3rd Party Boards
1

Hi everyone.
After many prototype i decided to create a dedicated board based on the 32U4, self designed and created

But now i've trouble about flashing the chip. When i try to burn (with UNO and ArduinoISP sketch)
I've some message about wrong device signature. Sometimes it's 0x008000, sometimes 0xfffffff i've tried to change wires, board (same results with 2560 or pro micro) or crystal and nothing.

Here is my wiring to set a 5V/16Mhz

image
image907×627 13 KB

Any error on my schematic ?

Thanks for your help

2

I don't see a pull-up on your Reset line.

That is typically an indication that one or more of the 6 ICSP wires (Reset, MOSI, MISO, SCK, +5V, and Gnd) is connected incorrectly.

3

@johnwasser yup i agree and it's a litle bit better with a 10k+5v on reset. when i'm not 0x000000, i've the device signal. sometime it allow me to try to flash but fail the check step

4

Just to be sure, i connect
PIN 32U4 | UNO
9 (TP30) | D13
10 (TP29) | D11
11 (TP24) | D12
13 (TP31) | D10
5 V (TP16)| 5V
GND (TP17)| GND

Is it correct ?

5

PIN 32U4 | UNO
SCK=9=TP30 | D13=SCK
MOSI=10=TP29 | D11
MISO=11=TP24 | D12 MISO
RESET=13=TP31 | D10 SS
5 V (TP16) | 5V
GND (TP17) | GND

Looks correct. How securely are the wires attached? Soldered? Socketed?

6

i've soldered male pins on test point 30,29,31,24,17,16 (i placed them on side with the needed space between to plug it on a BreadBoard) and BB to uno with male to male wires

image
image362×795 15.7 KB

7

I've check with oscilo MISO seem little bit low (under 2.3V or 2.6V in max) maybe change some capacitor ?

8

Have you checked at the UNO? If you aren't getting 5V out of the UNO on Pin 12 (MISO) then something is wrong outside your board.

They are just soldered to the surface? That is going to be fragile. You should have plated-through-holes to solder the pins into.

9

Finaly i've found my mistake (with the error for reset)
in official datasheet, we can see this :

image
image970×702 29.7 KB

For THIS case, gnd is not connected to Ugnd (ground from USB)
in my case i deal with battery, regulator stuff.. so i'm on this case :
image
image1036×662 31.7 KB

And in this way, VBUS is ONLY connected with VUSB (i connect all on my schema and this is the problem). On my pcb i've isolate VBUS by cutting way and now every time when i try, i can burn the bootloader

Testing pad is enough for temporary wire / solders. I'm agree it's fragile but when bootloader is burn (and usb test ok) i desolds them

10

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.