Boot Program Read Command Selection for Memory Controllers
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Solution Overview
Problem
Existing information processing apparatuses face inefficiencies in boot program reading due to the use of generic read commands that are slow, leading to increased time needed to determine and execute the appropriate read command for different memory types, particularly when using memories that support high-speed data transfer.
Innovation Solution
The apparatus selects a read command supported by the connected memory type by utilizing a memory controller with an operation mode setting unit that sets the ROM access specification based on a stored ROM access pattern, allowing the CPU to read the boot program using the most suitable command without accessing the memory storing the boot program.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a generic read command that can be used for any memory type is used, then the boot program can be read regardless of the memory type connected, but the data transfer speed is slow and the time to read the boot program increases
Solution Approach 1:
The invention applies preliminary action by pre-storing ROM access patterns (including command codes, address formats, and data formats) in a storage unit before the boot program reading process. The CPU retrieves the appropriate access pattern based on the connected memory type and configures the memory controller accordingly, avoiding the need to use slow generic commands during the actual boot program reading phase.
2Speed
If a high-speed read command specific to certain memory types is used, then the data transfer speed increases, but the command cannot be used with all memory types
Solution Approach 1:
The invention implements dynamics by making the memory controller's operation mode configurable and adaptable. The controller dynamically switches between different ROM access patterns (single SPI, quad SPI, dual I/O) based on the type of memory connected. This allows the system to use high-speed commands when appropriate memory types are detected while maintaining compatibility with various memory configurations.
3Ease of operation
If the system determines the appropriate read command by accessing the memory storing the boot program, then the correct command can be selected, but additional memory access time is required
Solution Approach 1:
The invention applies copying by pre-storing multiple ROM access patterns (including command codes, address formats, and data formats for different memory types) in a separate storage unit. Instead of accessing the boot program memory to determine the correct command, the CPU copies the appropriate access pattern from the storage unit to configure the memory controller, thereby avoiding additional access to the boot program memory itself.
Data Source
AI summary
An information processing apparatus includes a control unit to execute a program, a first storage unit, a second storage unit, and an output unit. The first storage unit stores a first program to be executed by the control unit. The second storage unit stores a second program to be executed by the control unit. The output unit receives, from the control unit, a read command for reading the second program from the second storage unit. The output unit output, to the second storage unit, a corresponding command corresponding to the received read command and corresponding to an operation mode having been set to the output unit. Before transmitting, to the output unit, the read command for reading the second program from the second storage unit, the control unit sets the operation mode of the output unit according to the first program stored in the first storage unit.