I consider this a bug.
If a Controlled Buffer component's input pin is floating (U), it generates an error (E) on its output pin if the buffer is enabled.
The correct behavior would be to generate U on the buffer's output pin when its input pin is U and the buffer is enabled. In other words, the buffer should always pass the state of its input pin (0, 1 or U) to its output pin when enabled.
The only time the buffer should generate E on its output pin is when its Enable pin is disconnected or its input pin is E.
This bug makes it impossible to create a bi-directional buffer using two controlled buffers with their outputs tied to each other's inputs (like the 74245 8-bit bus transceiver).
Interestingly, the latest version of L-E (8.03) includes a custom 74245 IC that works correctly (both the A and B sides can both be floating, with no errors when enabled). But I can't build that same IC using L-E's Controlled Buffer components because of this bug.
I consider this a bug.
If a Controlled Buffer component's input pin is floating (U), it generates an error (E) on its output pin if the buffer is enabled.
The correct behavior would be to generate U on the buffer's output pin when its input pin is U and the buffer is enabled. In other words, the buffer should always pass the state of its input pin (0, 1 or U) to its output pin when enabled.
The only time the buffer should generate E on its output pin is when its Enable pin is disconnected or its input pin is E.
This bug makes it impossible to create a bi-directional buffer using two controlled buffers with their outputs tied to each other's inputs (like the 74245 8-bit bus transceiver).
Interestingly, the latest version of L-E (8.03) includes a custom 74245 IC that works correctly (both the A and B sides can both be floating, with no errors when enabled). But I can't build that same IC using L-E's Controlled Buffer components because of this bug.