Video ram having an option of a full sam and a half sam

A video random access memory device that can be connected during manufacture to operate as one of a full serial access memory and a half serial access memory device, the device comprising:

• a serial access memory comprising:
• a first interleaved group of serial access memory cells, each transferring data with a respective cell of said random access memory accessed when a first most significant bit of an accessing address signal has a first logic level, and
• a second interleaved group of serial access memory cells, each transferring data with a respective cell of said random access memory accessed when said first most significant bit of said accessing address signal has a second logic level, said second interleaved group of serial access memory cells being interleaved with said first interleaved group of serial access memory cells with respect to a serial output sequence of data stored in said serial access memory;
• a random access memory comprising:
• a first interleaved group of random access memory cells, each being accessed when said first most significant bit of said accessing address signal has said first logic level, and
• a second interleaved group of random access memory cells, each being accessed when said first most significant bit of said accessing address signal has said second logic level, said second interleaved group of random access memory cells being interleaved with said first interleaved group of random access memory cells with respect to said serial output sequence of data stored in said serial access memory;
• connection means, alterable during manufacture of said device, for configuring said video random access memory device to operate as one of a full serial access memory device and a half serial access memory device;
• a plurality of transfer gates for transferring data between said first and second interleaved groups of random access memory and said first and second interleaved groups of serial access memory;
• and
• a serial counter generating serial addresses for addressing said serial access memory.

In a video random access memory device that can be connected during manufacture to operate as one of a full serial access memory device and a half serial access memory device, the device comprising:

• a random access memory;
• a serial access memory receiving data transferred from said random access memory;
• and
• address switching control means connected to said random access memory for switchably exchanging connections between a first address bit and a second address bit of an external address signal external to said video random access memory device and respective internal address bits of an internal address signal addressing said random access memory, said exchange of said connections changing said serial access memory between operation as a full serial access memory and operation as a half serial access memory.