Semiconductor Command Decoder for Pin Reduction
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Solution Overview
Problem
Reducing the number of CA pins in semiconductor memory for mobile devices to minimize chip size and power consumption leads to increased clock cycles for command transmission and more command codes, resulting in higher information bit consumption.
Innovation Solution
Implementing a command decoder with a chip select controller and command decode block that receives command address signals and decodes commands across four clock cycles, allowing for fewer variations in command codes and efficient transmission using internal clock signals, thereby reducing the number of clock cycles required for command processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of CA pins is reduced to minimize chip size, then chip size and power consumption are reduced, but the number of clock cycles for command transmission increases
Solution Approach 1:
The command transmission process is segmented into multiple clock cycles, with different command components (command code, address, bank information) being transmitted in separate cycles. This allows the use of fewer CA pins while maintaining command transmission capability through time-division multiplexing.
Solution Approach 2:
Command transmission utilizes periodic clock cycles to convey different portions of command information. By alternating between different command components across periodic clock cycles, the system achieves efficient data transmission with reduced pin count.
2Device complexity
If commands are divided into multiple clock cycles to reduce CA pin count, then fewer pins are needed, but more command codes are required to distinguish sub commands
Solution Approach 1:
The command code is transmitted in the first clock cycle before the address and bank information. This preliminary transmission of the command code allows the memory controller to prepare for subsequent address decoding without requiring additional distinguishing codes in later cycles.
Solution Approach 2:
The system dynamically assigns different CA pin functions across different clock cycles. The same pins that carry command codes in the first cycle are reused for address transmission in subsequent cycles, optimizing pin utilization and reducing the total number of pins required.
3Reliability
If four clock cycles are used for one command, then complete command information can be transmitted, but fewer commands can be conveyed during a predetermined number of clock cycles
Solution Approach 1:
The four-clock cycle command structure is segmented into distinct functional portions: command code in the first cycle, address information in the second cycle, and bank information in the third cycle. This segmentation allows for reliable complete command transmission while enabling parallel processing of different command components.
Solution Approach 2:
The memory controller continuously processes command components as they arrive across the four clock cycles, rather than waiting for the complete four-cycle sequence to finish before beginning processing. This continuous action maintains high command throughput while ensuring complete command transmission.
Data Source
AI summary
Method and Apparatuses for of decoding commands for a semiconductor device are described. An example method includes receiving a portion of a command at first and second clock cycles; validating the portion of the command received at the first and second clock cycles at a third clock cycle when a chip select signal indicates a first state and continuing to receive the remaining portion of the command at the third clock cycle and a fourth clock cycle so that the command can be completely received by the semiconductor device by the fourth clock cycle; and invalidating the portion of the command received at the first and second clock cycles at the third clock cycle when the chip select signal indicates a second state different from the first state, so that a new command can be input to the semiconductor device at the third clock cycle.