Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorFPGA IO configed as 1.8V not working
Hi,
I read from the device handbook and get that the cyclone2 devices support multi-voltage IO standards, such as 3.3/2.5/1.8/1.5 volt. I change the IO voltage to 1.5 volt in the device options setting and re-compile, download it to the board and find the output is still 3.3v. Setting them to 2.5 or 1.8v is not working too. Am I doing something wrong? https://www.alteraforum.com/forum/attachment.php?attachmentid=37164 Replies
Altera_Forum--- Quote Start --- so I hope the IO voltage setting has only information purpose. --- Quote End --- This should be true at least for MAX II. With FPGA, the I/O standard also affects the interpretation of the current strength setting.- Altera_Forum--- Quote Start --- The I/O voltage setting has the purpose of informing Quartus about the hardware enviroment. The actual voltage is set by connecting the VCCIO pins to a respective supply. Apparently your board (I guess, a development kit) has all or most VCCIO pins wired to 3.3V. --- Quote End --- Does the IO voltage setting have purpose other than informing quartus? eg, if I want to use max-ii device as level shifter, but one side of the shifter's voltage is variable, you know... so I hope the IO voltage setting has only information purpose. then i can chose one setting and change VCCIO without re-compile
- Altera_Forum
The I/O voltage setting has the purpose of informing Quartus about the hardware enviroment. The actual voltage is set by connecting the VCCIO pins to a respective supply. Apparently your board (I guess, a development kit) has all or most VCCIO pins wired to 3.3V.
- Altera_Forum
Are the output pins voltage related to those IO/VREFBxNx?
