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ATMEGA32U2 connection problem
ATMEGA32U2 connection problem –
Hello PS freaks, I am having problem with my self-made dongle based on ATMEGA32U2 MCU. I have soldered and attached everything according to my_project.zip (schematic,board). All the stuff looks pretty good, but...
After connecting to PC nothing happened... PC do not recognize any USB device. In HW manager USB port looks like there is no device connected...
Of course I have performed the bootloader start (press and hold WHB, press RESET, release RESET, release HWB). And nothing...
So I have started the measurings...
The pins: AVCC(32), UVCC(31) and VCC(4) are connected to +5V (correct value)
pins: UGND(28) and GND(3) are connected to GND potential... (correct)
pin UCAP (27) shows 3,3V on it. (correct value)
pin 24 - RESET is after start on +4,71V... (correct value)
pin 13 - HWB is connected to +5V via pushbutton "HWB"... (correct value)
All the ports (PB,PC,PD) are on something around 70-100mV. (should be correct for unprogrammed MCU).
BUT!!! Pins DATA- and DATA+ (30,29) have both 0(zero)Volts!!! I think there should be bus voltage (3,3V). So it looks like USB upstream and downstream ports are turned OFF! (Thats just my oppinion). I will try to catch some signals after connection on oscilloscope, to make sure, that there is no data transfer.
Now I am bit confused, what is wrong... So I kindly ask anyone, Who has some idea how to solve this fu*king problem!
Oscilloscope meassuring has shown what I did expect... no data transfer on USB bus...
Last edited by nasratr; 12-05-2010 at 04:24 PM.
You have put C2 and C3 with 15nF instead of 15pF !!!
Replace them with the correct value
thanks, I will try... But I think, that HW bootloader works with internal clock source
PROBLEM SOLVED!!! –
The main problem was really value of coupling C for X-TAL!!!
I have replaced them vith 18nF and everything works!!!
Thank you for advice!
Take care Alfa1962