No Clock on AT90USB162-16AU

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Hi,

New to AVR parts but have used Microchips in the past for several projects.

 

MY issue is when trying to read the device ID I get the error "Unable to enter programming mode. The read device ID does not match the selected device or any other supported devices"  Using an Atmel ICE and it works on a different board/project.

The physical board is of my design but made by a board house so its not a breadboard. 

When putting a scope on Xtal pins (using an external 16MHz crystal on pins 1 and 2 but with 20pF instead of 22pF caps) the clock is not running. I am guessing that's why it wont enter programming mode.  The chips are new from digikey. 

 

This is happening on 2 different boards. Shouldn't the clock run by just powering it on? I double checked and have VCC tied to pins 4,32,31 Pin 3 is grounded and I have a 1uf cap on 27 (Ucap)

 

 The programming header on the board is connect as follows:

Header - Pin

1 17 (MISO)
2 VCC +5V
3 15 (SCK)
4 16 (MOSI)
5 24 (RST)
6

 GND

 

This looks correct to me unless I missed something.

 

Any ideas would be appreciated.

 

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jschmied wrote:
Shouldn't the clock run by just powering it on?
Yes (edit : unless RESET active?)

The factory USB DFU bootloader should be present.

USB DFU Bootloader Datasheet via AT90USB162 - 8-bit AVR Microcontrollers

 

"Dare to be naïve." - Buckminster Fuller

Last Edited: Fri. Dec 13, 2019 - 12:16 AM
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Here is the schematic for the Olimex board for the AT90USB162:

Note C1, C2, and C11.  These should be located close to the microcontroller pins.

 

Hear is the pinout for the ISP header:

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jschmied wrote:
This is happening on 2 different boards. Shouldn't the clock run by just powering it on?
What state is the AVR in? Has it ever been ISP programmed up to this point? If so what were the fuses set to.

 

By default AVRs start life clocking from an internal RC oscillator. Unless the CLKOUT fuse has been set it will show now external signs (clock pulses on any pins) that the internal clock is running. If it has had the CKSEL fuses set to select some form of external clock (probably a crystal) then if there is a crystal with caps across the XTAL1/XTAL2 pins then activity may be seen on those pins. But it's quite possible to connect a crystal, apply power and still see nothing if the fuses are still set to intRC,

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clawson wrote:
By default AVRs start life clocking from an internal RC oscillator.

 

     From the AT90USB162 Datasheet:

6.3.1 Default Clock Source
The device is shipped with low power crystal oscillator and with the fuse CKDIV8 programmed.

 

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Thanks for the replies:

@ gchapman - the reset line is HI (5V), I would think the factory USB bootloader is present. They are new chips.

 

@Chuck99 - thanks for the schematic. Its similar to what I have . I should have attached with the original post.

 

@ clawson - they have not been programmed, It was never able to enter programming mode from the beginning.  When powering the board I also use only the 5V and GND pins on the USB connector. The data lines are cut in the cable. 

 

I saw some suggestions in other posts to introduce a separate clock signal on pin 1. It must be something simple that I am overlooking.

Attachment(s): 

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What is the part number of the 16MHz crystal?

I'm asking because your schematic shows that it has 4 leads, which is unusual.

 

What is the part number of the two 20pF capacitors?

Did you measure the capacitors (off the board)?

Using the wrong part could explain no oscillation.

 

jschmied wrote:
When putting a scope on Xtal pins (using an external 16MHz crystal on pins 1 and 2 but with 20pF instead of 22pF caps) the clock is not running.

When probing the Xtal pins, it is best to use a 1K resistor in series with the scope probe.

The resistor isolates the oscillator circuit from the probe's input capacitance.

Also, be sure that the probe is set to 10x.

 

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The crystal is an Epson TSX-3225, it does have 4 pads, 2 of which are grounded. I also tried removing this crystal and using an ECS-120-20-4x ( I know its a 12MHz) but wanted to see if it would at least oscillate, it didn't either.

 

The caps are Yageo CC0603JRNPO9BN200. Measured one off the board at about 30pF. Using the same caps and the ECS crystal above works on a different Atmega project. Havent been able to inject a 8MHz signal yet on the pin.