This is my first post so hello to all! I'm just starting with fpga programming. I bought a cheap dev board from ebay: Ebay-Artikel Nr. 400630255386 As an initial test I wanted to see if I can get the leds light up. I don't have board description so based on the wiring the leds are probably connected to 3 of the first 10 pins somewhere. So I wrote code to set these pins to 1 but they don't work. I tried with 0 too maybe if the leds are active low. Output levels are set to LVTTL, as I see from the wiring all IO blocks get 3.3V. I supply it from 6V instead of 5 but that's not a problem as the stabilizer can handle it. JTAG threw me a "chain broken" message so I use AS mode. Tried restarting the board after programming. I use a chinese USB blaster with the newest 64bit win7 drivers and Quartus 6. Does anyone have some ideas where might the problem be? Thanks!
Hi bebel! what is your HDL that you wrote leds module. i know verilog, if you want to code verilog, i can help you if you want, my skype: tv_long
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Edited by User
The code is as simple as can be, that's why I didn't think it would be
the cause:
entity fpga is
port(
F1: out std_logic;
F2: out std_logic;
F3: out std_logic;
F4: out std_logic;
F5: out std_logic
);
end fpga;
architecture behv2 of fpga is
begin
F1 <= '0';
F2 <= '0';
F3 <= '0';
F4 <= '0';
F5 <= '0';
end behv2;
Ohh do remember you have an onboard OSC connected. Quartus seems to default unused pins to : output driving GND You might get a race with the unused FPGA Osc pin (GND) and the OSC at 3.3v You could either make a dummy vhdl statement using the the OSC , or tell Quartus to set unused pins as 3-stated inputs with weak pullups /Bingo
:
Edited by User
Hey thanks Bingo, it works now! 1) The leds are active low so 0 had to be set. 2) Tri-stating unused pins helped, otherwise the leds are very dim. 3) I had to detach AS cable from the board to reboot from eprom. Earlier I only removed the power supply but it seems that's not necessary. Cheers!
bebel wrote: > 2) Tri-stating unused pins helped, otherwise the leds are very dim. > Cheers! That sounds like you had a problem with pins driving GND , and pulling your 3v3 down. Hope your Osc is ok. You could try the tests in the zip , they use the Osc. /Bingo
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