quartus hierarchy strangeness

Hi, I've been getting some strange behaviour compiling hierarchical vhdl files in quartus. The code is a vhdl reworking of the pong.v & vga files from fpga4fun.

When written as separate files with a top level .bdf or with a top level .vhd instantiating the other files as components or any other variation of multple files fails to synthesise correctly.

Regardless of which variation of the above is tried, it always synthesises the same component.

When written as a single .vhd file with a .bdf for the pin connections it synthesises correctly.

the initial structure of the files was

top-level.bdf-| | pong.vhd------| | hysnc.vhd-+

hsync was a dependency of pong.vhd and was the only code that would actually be synthesised when the compiler focus was set to the top-level .bdf in spite of the synthesis tool reporting 'found 2 design units in pong.vhd' etc,etc.

compiling/sysnthesising pong.vhd on its own results in no errors.

Having googled without finding a solution, does anyone have any suggestions. ( other than sticking with verilog :) as it's for a student exercise)

-- Nigel Gunton Phone : +44/0 117 32 83167 /"\ Senior Lecturer, School of Electrical & Computer Engineering, \ / CEMS, University of the West of England, Bristol. X ASCII Ribbon Campaign against HTML email & microsoft attachments / \

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nigel.gunton
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Oops, turned out the problem lay with a missing line of code in one of the files assigning a signal to an output. This meant that most of the logic in the parent file was 'dropped' by the compiler and synthesis stages. Only it was doing it without warning or error, hence the focus of attention being on the compiler behaviour.

memo to self: must upgrade to current tool versions :)

Thanks to all those who responded to me directly.

nigel g.

-- Nigel Gunton Phone : +44/0 117 32 83167 /"\ Senior Lecturer, School of Electrical & Computer Engineering, \ / CEMS, University of the West of England, Bristol. X ASCII Ribbon Campaign against HTML email & microsoft attachments / \

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nigel.gunton

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