Asynchronously-resettable decoder with redundancy

In a decoder in a memory module including a first memory cell group and a second memory cell group, a method of selecting at least the second memory cell group comprising:

• a. inputting a signal;
• b. coupling a first memory output with the first memory cell group;
• c. coupling a second memory output with the second memory cell group;
• d. decoding an address in the event of a fault detected on the first memory output when the decoder is in service;
• and
• e. enabling the second memory cell group responsive to a group-select signal.

In a memory module including a plurality of memory cell groups and a decoder including a synchronous portion and an asynchronous portion, a method of selecting between the memory cell groups comprising:

• a. receiving and responding to a clocked signal;
• b. coupling the asynchronous portion with a selected memory cell group;
• c. isolating the synchronous portion from the asynchronous portion;
• d. reselling the decoder in response to an asynchronous reset signal independent of the clocked signal;
• d. inputting a signal;
• e. coupling a first memory output with a first memory cell group;
• f. coupling a second memory output with a second memory cell group;
• g. decoding an address in the event of a fault detected on the first memory output when the decoder is in service;
• and
• h. enabling the second memory cell group responsive to a group-select signal.