Generation of memory column addresses using memory array type bits in a control register of a computer system
First Claim
1. A memory controller circuit for generating column addresses from addresses communicated on a bus, comprising:
- a control register for storing a memory array type code indicating a particular one of a plurality of memory array types; and
a column address selector circuit having inputs receiving a plurality of address lines of the bus, having outputs, and having control inputs receiving the contents of said control register, for selectively communicating a number of the address lines to its outputs as a column address responsive to the memory array type code stored in said control register.
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Abstract
A method and circuitry for generating column addresses for a memory based upon signals on an address bus in a computer system, are disclosed. The disclosed circuitry is provided within a memory controller unit of a microprocessor unit, and includes circuitry for receiving address lines from the address bus, and for receiving control register bits indicating a particular memory array type. The memory array type indicates the number of the address bits which are to be forwarded to the memory as the column address, rather than as the row address. The memory is of a dynamic random access memory (DRAM) type, for which row and column addresses are time-multiplexed over the same lines. The microprocessor unit may be integrated onto a single integrated circuit chip with the memory controller, and may include a first level write-through cache in combination with a significantly smaller second level write-back cache. The disclosed microprocessor unit also includes circuitry for controlling the access to configuration registers, and circuitry for determining the sizes of individual memory banks in the memory.
66 Citations
15 Claims
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1. A memory controller circuit for generating column addresses from addresses communicated on a bus, comprising:
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a control register for storing a memory array type code indicating a particular one of a plurality of memory array types; and a column address selector circuit having inputs receiving a plurality of address lines of the bus, having outputs, and having control inputs receiving the contents of said control register, for selectively communicating a number of the address lines to its outputs as a column address responsive to the memory array type code stored in said control register. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating a memory controller circuit to generate row and column addresses for a memory, comprising the steps of:
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storing a memory array type code in a control register, the memory array type code indicating a particular one of a plurality of memory array types; receiving a memory address on a plurality of address lines of a bus; generating a row address from a first plurality of address lines of the bus, selected responsive to the memory array type code stored in the control register; and generating a column address from a second plurality of address lines of the bus, selected responsive to the memory array type code stored in the control register. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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Specification