AR# 4434: Foundation, Spartan: Why can MD1 be placed in schematic, but causes error in implementation?
AR# 4434
Foundation, Spartan: Why can MD1 be placed in schematic, but causes error in implementation?
Description
Keyword: foundation, spartan, mode pins, MD1
Urgency: Standard
General Description: In the Foundation design entry tools, MD1 can be placed in the design, but when implementing the design, an error is generated, regarding the illegal use of the mode pins.
Solution
In Foundation 1.4, the XC4000E part library is used to target Spartan parts. The XC4000E part has more than 1 mode pin and allows the use of these pins after configuration. The Spartan part has 1 mode pin (MD0). This single mode pin is a dedicated pin, preventing user use of the pin after configuration. Any design intending to use the Spartan mode pin after configuration must be modified to use general user I/O for that function.