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December 1, 2006
I am using the Wifly shield with an Arduino Uno R3, using the latest Roving firmware in the WiFly module. The sketch works fine as long as I’m connected to the computer via USB, but not if I run the Uno from a wall-wart using the barrel power connector. Note that the Uno/WiFly does not send any data to the host computer, it’s only getting power from the USB connection.
In monitoring the SPI pins, I see that at least the SCLK and SS signals disappears as soon as the first character is received over the WiFly connection. However, if I reset the Uno (hit the reset pushbutton) without pulling power, then everything works fine after that. The SPI signals are correct, and dont' go away.
I’ve tried slowing down the reset pins on both the Arduino and WiFly SPI UART with caps, using Spi_Serial.begin() more than once, various delays in setup (in case the power is coming on too fast), etc, but can’t find the problem. I’ve tried various wall-warts and power supplies to make sure that the voltage to the Arduino is fine.
Has anyone else run into this? Where the Arduino/WiFly works fine from USB, but not from external power?
about 4 years ago
I’m not sure about interfacing to a 5V CPU.
You can create address lines and bidirectional data lines with the FPGA pins themselves. Declaring wires/registers as INOUT allows pins to be bidirectional, under control of the FPGA, or via a separate direction pin into the FPGA. I use INOUT to interface bidirection data to memory devices external to the FPGA.
Is that what you mean?
The two-part board is approx 3-3/16 wide by 6-¼ long, with the FPGA part being 3-½ long. The two boards can be cut apart, but then you need to supply power regulation, flash, etc.
It has taken a while to get back to this board. I have three Digilent Nexys2 boards, and they are great to use with all the “test hardware”, but for sheer FPGA pinout availability, this Sparkfun board is hard to beat.
I have the parallel port programmer from SF, but I also just got a Xilinx USB Platform Cable from a Chinese vendor for $60 via ebay, and it just programmed this board fine, using ISE Webpack 11.1. I tried to buy it from Hummingosand, but after two months it never came - check the seller feedback! Second order went to hongkong_electronics, it took about two weeks to arrive.
I’m using the “flying leads” cable right now, but can program both the FPGA directly, and the onboard flash AT45DB161D(although the flash hangs at the end).
For those that cannot use a parallel port any longer, and can figure Impact out, this USB programmer will work. Now, off to try adding the SF Wiznet 830 module to the SF FPGA board…
about 5 years ago
I was able to get mine to work OK, but I built up a homebrew version of the development board that Wiznet has for this module. I can get the LEDs to turn on/off, read the switches and pots, and display messages on the LCD display. I bought the little temp sensor chip from digikey, and that works as well. I did need to change the IP address, and enable DHCP, through the Wiznet configuration program, if I remember correctly. The enet leds work fine too.
Wiznet has a document for their development/EVM board, which shows how to use the module with the existing code on the module, go to their website. Then, try to change that after confirming the existing stuff works fine.
I plugged by Wiznet enet cable right into a standard switch port on my LAN, it gets an IP address from the router just fine, after I config'ed it to do that.
I have not tried to modify the existing code yet. But, I believe all the code is available, either here at Sparkfun, or on the Wiznet website.
I’m happy so far…
No public wish lists :(
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