Microprocessor system
First Claim
1. A microprocessor system comprising:
- microprocessor means, coupled to a first 2n-bit data bus and a first control bus, said first 2n-bit data bus including first and second data buses each having an n-bit data width, and responsive to an input 2n-bit data transfer command, for outputting a transfer instruction onto said first control bus, for selectively inputting into said microprocessor means 2n-bit input data on said first 2n-bit data bus, and for selectively outputting from said microprocessor means 2n-bit output data onto said first 2n-bit data bus, an operation state of said microprocessor means being held in accordance with a wait instruction input thereto;
read/write control means, coupled to said first control bus and a second control bus and responsive to the transfer instruction from said microprocessor means and a disable instruction input thereto, for selectively and sequentially generating and outputting onto said second control bus first and second transfer instructions, the first and second transfer instructions being associated with first and second transfer cycles, respectively;
bus converter means, coupled to said first 2n-bit data bus and a second 2n-bit data bus including third and fourth data buses and responsive to an input bus conversion instruction, for selectively and sequentially inputting into said bus converter means first n-bit input data ("FNID") and second n-bit input data ("SNID") on said third data bus, for substantially simultaneously outputting from said bus converter means the FNID and SNID as the 2n-bit input data onto said first 2n-bit data bus, for selectively inputting into said bus converter means the 2n-bit output data comprising first n-bit output data ("FNOD") and second n-bit output data ("SNOD") on said first 2n-bit data bus, and for sequentially outputting from said bus converter means the FNOD and the SNOD onto said third data bus;
a device having the n-bit data width, coupled to said third data bus and said second control bus and responsive to the first and second transfer instructions, for selectively and sequentially outputting from said device the FNID and SNID onto said third data bus, and for selectively and sequentially inputting into said device the FNOD and the SNOD on said third data bus; and
timing generating means, coupled to said second control bus and responsive to the first and second transfer instructions from said read/write control means and an input address, for generating and outputting to said bus converter means the bus conversion instruction, for generating and outputting to said read/write control means the disable instruction between the first and second transfer cycles, and for generating and outputting to said microprocessor means the wait instruction from a first timing during the first transfer cycle to a second timing during the second transfer cycle.
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Abstract
A microprocessor system is configured by connecting an n/2-bit memory and/or I/O to an n-bit microprocessor. The system has a read/write controller for enabling/disabling a read/write control signal for accessing the memory and/or I/O, an address latch counter for latching and updating the address, a bus converter for converting the data bus through which the data is transferred, and a timing generator. The timing generator comprises a detector for detecting that the instruction executed by the microprocessor is a word transfer instruction for the memory and/or I/O, a counter for counting the number of times a read/write control signal is generated and a timing controller for generating various timing control signals when the word transfer instruction for the memory and/or I/O is executed. When the microprocessor performs the word transfer instruction for the memory and/or I/O, the read/write control signal is enabled and disabled to perform two access cycles. The word transfer instruction can be automatically converted to two 1/2 transfer instructions.
191 Citations
20 Claims
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1. A microprocessor system comprising:
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microprocessor means, coupled to a first 2n-bit data bus and a first control bus, said first 2n-bit data bus including first and second data buses each having an n-bit data width, and responsive to an input 2n-bit data transfer command, for outputting a transfer instruction onto said first control bus, for selectively inputting into said microprocessor means 2n-bit input data on said first 2n-bit data bus, and for selectively outputting from said microprocessor means 2n-bit output data onto said first 2n-bit data bus, an operation state of said microprocessor means being held in accordance with a wait instruction input thereto; read/write control means, coupled to said first control bus and a second control bus and responsive to the transfer instruction from said microprocessor means and a disable instruction input thereto, for selectively and sequentially generating and outputting onto said second control bus first and second transfer instructions, the first and second transfer instructions being associated with first and second transfer cycles, respectively; bus converter means, coupled to said first 2n-bit data bus and a second 2n-bit data bus including third and fourth data buses and responsive to an input bus conversion instruction, for selectively and sequentially inputting into said bus converter means first n-bit input data ("FNID") and second n-bit input data ("SNID") on said third data bus, for substantially simultaneously outputting from said bus converter means the FNID and SNID as the 2n-bit input data onto said first 2n-bit data bus, for selectively inputting into said bus converter means the 2n-bit output data comprising first n-bit output data ("FNOD") and second n-bit output data ("SNOD") on said first 2n-bit data bus, and for sequentially outputting from said bus converter means the FNOD and the SNOD onto said third data bus; a device having the n-bit data width, coupled to said third data bus and said second control bus and responsive to the first and second transfer instructions, for selectively and sequentially outputting from said device the FNID and SNID onto said third data bus, and for selectively and sequentially inputting into said device the FNOD and the SNOD on said third data bus; and timing generating means, coupled to said second control bus and responsive to the first and second transfer instructions from said read/write control means and an input address, for generating and outputting to said bus converter means the bus conversion instruction, for generating and outputting to said read/write control means the disable instruction between the first and second transfer cycles, and for generating and outputting to said microprocessor means the wait instruction from a first timing during the first transfer cycle to a second timing during the second transfer cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A data transfer apparatus comprising:
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bus converter means, coupled to a first 2n-bit data bus including first and second data buses, each of said first and second data buses having an n-bit data width, and to a third data bus having the n-bit data width, and responsive to an input first conversion instruction, for selectively and sequentially inputting into said bus converter means first n-bit input data ("FNID") and second n-bit input data ("SNID") on said third data bus, and for substantially simultaneously outputting from said bus converter means the FNID and SNID as the 2n-bit input data onto said first 2n-bit data bus; and timing generating means, responsive to input first and second transfer instructions and an input address, the address being associated with the FNID and SNID, for generating and outputting to said bus converter means the first bus conversion instruction and for generating a disable instruction between first and second transfer cycles, the first and second transfer cycles being associated with the first and second transfer instructions, respectively; read/write control means, responsive to an input 2n-bit data transfer instruction and to the disable instruction input from said timing generating means, for selectively and sequentially generating and outputting to said timing generating means the first and second transfer instructions. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of applying a 2n-bit data transfer instruction to a device having an n-bit data bus width, said method comprising the steps of:
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performing a first access cycle and selectively performing a second access cycle, in accordance with the 2n-bit data transfer instruction and first and second addresses; sequentially transferring first n-bit output data ("FNOD") and second n-bit output date ("SNOD") constituting 2n-bit output data on a first 2n-bit data bus to the device through a n-bit data bus to which the device is coupled, in the first and second access cycles, respectively; and holding first n-bit input data ("FNID") on the n-bit data bus to output the held data to the 2n-bit data bus together with second n-bit input data ("SNID") on the n-bit data bus, as a 2n-bit input data, the FNID and the SNID being output from the device onto the n-bit data bus in the first and second access cycles, respectively, and the first and second access addresses being associated with the FNOD and SNOD or the FNID and SNID. - View Dependent Claims (19, 20)
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Specification