Comments on: Benito: My first at90USB162 project.

By: paul

paul — Thu, 01 Jan 1970 00:00:00 +0000

You should really locate C3 right next to pins 3 and 4, with direct, short traces. There’s really no reason not to, since there’s plenty of room under the crystal. Or better yet, put another capacitor there. The value doesn’t matter, 0.01 uF with short traces is a LOT more effective that 1 uF on the other side of the board.

Virtually all the current consumed by the chip is via those two pins, and it’s all high speed current pulses. Locating the cap on the other side of the board makes all that high frequency current travel though a pretty horrific loop since the Vdd trace runs around the right edge of the board and the primary ground return is back up and slightly to the left (on the top side).

Atmel recommends a 10uF capacitance capacitor on the Vbus line (section 19.3.3, Design Guidelines, page 187). That’s mainly because of worry over poor power quality from the PC and the high voltage spike during dynamic disconnect (due to current still flowing in the inductive lines inside the USB cable). The FTDI chip suggests a series inductor, which is great for protecting your device against the spike, but totally goes against the letter and spirit of the USB spec, where both host and device and supposed to put low ESL capacitance on the bus to share the burden of suppressing that spike.

Single layer boards are difficult, and it’s pretty impressive you got it all on there. Sometimes it’s just not possible to do good decoupling on a single layer board, but in this case (assuming you’re only going to use 1 cap), you can easily put it right next to pins 3 & 4 where it will do the most good.

By: ax

ax — Thu, 01 Jan 1970 00:00:00 +0000

I am running Ubuntu, I installed the Ubuntu packages for binutils-avr and gcc-avr but had to install avr-libc from source because (at least at this time) Ubuntu doesn’t have a package for avr-libc-1.6.2. I installed avr-libc-1.6.2 with prefix /usr/ because I couldn’t figure out how to use it from /usr/local/.

I did run into the problem where the linker doesn’t find crtusb162.o, but on my platform it is looking in avr5/

so what I did was:
cd /usr/avr/lib/avr5/
sudo ln -s ../avr3/crtusb162.o

Then the Benito software will build (though my version of avr-size does not take the option –mcu=at90usb162, so I had to change it from:
ELFSIZE = $(SIZE) –mcu=$(MCU) –format=avr $(TARGET).elf
to:
ELFSIZE = $(SIZE) –target=elf32-avr $(TARGET).elf

Is this even correct?

Alternatively (with out having to use sudo) you could do:
avr-gcc -dumpspecs > /tmp/specs
then substitute:
mmcu=at90usb162 mmcu=avr5
with:
mmcu=at90usb162 mmcu=avr3
(I use vim :%s/mmcu=at90usb162 mmcu=avr5/mmcu=at90usb162 mmcu=avr3)

Then edit the CC target in your Makefile to be
CC = avr-gcc -specs=/tmp/specs

Then you should be able to build.

(maybe you could put it in a better place and use it again later)

Anyways, with these two methods I was able to install the benito firmware onto my device (sudo make program). Then I did:
cat /dev/urandom > /dev/ttyACM0
and the light lights up!

By: apollo21

apollo21 — Thu, 01 Jan 1970 00:00:00 +0000

I have “AT90USB162″ and “AT90USB647″.
I want to use “AT90USB162″ for “ISP” and “JTAG”.
I want to use “AT90USB647″ for “Dragon”, but do you have the document?
How do you write in those firm ware?

[[Image:A test board|left|100x75px|]]

By: apollo21

apollo21 — Thu, 01 Jan 1970 00:00:00 +0000

As for Schematic which I watched, “Benito board rev 5″ frequency is not clear.
I supposed it to be “8MHz”.
I have holdings of “only “12MHZ” and 16MHz” unfortunately.
I intended I exchanged frequency in “Avrstudio4″, and to compile it, but was not able to find the method.
I want “five Benito board rev Firmware_12MHz”.
Is it difficult?

By: apollo21

apollo21 — Thu, 01 Jan 1970 00:00:00 +0000

I confirmed that AT90USB162 worked in “8MHZ” and “16MHZ” and “12MHZ” did not work.
I supposed that the voltage was right in reading it not having JTAG and HVPP, the voltage of HVSP that I made the trial of the pin arrangement and applied a pin arrangement as follows.
I can use 2-pin elsewhere when I use an oscillator in substitution for a crystal.[[Image:New pin arrangement|left|87x100px|]]

By: apollo21

apollo21 — Thu, 01 Jan 1970 00:00:00 +0000

Furthermore, a signal turned over and shared “RST_CTL” with “SS_RST”, and “RST_HZ_CTL reversed a signal, too” and saved Schematic and put up speed more.
[[Image:A voltage control circuit.|left|100x63px|]]

By: feurig

feurig — Thu, 01 Jan 1970 00:00:00 +0000

Because the chips built in dfu will work with 8 and 16, and I thought I read somewhere that 12 would work but I haven’t tested that.

By: mrbatu

mrbatu — Thu, 01 Jan 1970 00:00:00 +0000

I’m unable to download the project files including the at90usb.lbr eagle library. Is there someone who can help and send me this file?

Thanks in advance.

By: feurig

feurig — Thu, 01 Jan 1970 00:00:00 +0000

After some experimentation and realizing that my 3 v circuit didnt work I found that I had better results with a 16mhz crystal. All benitos built out by me since november have 16mhz crystals.

By: feurig

feurig — Thu, 01 Jan 1970 00:00:00 +0000

I recently added a teensy++ entry and also a part for the 32u4 so I will reupload them shortly.