Memory Features
Modern microcontrollers (MCUs) contain internal memory for executing programs and storing data. There are multiple types of memory inside the MCU with varying purposes depending on the type of memory.
Types of Internal Memory
Program Flash Memory (PFM) | PFM is a non-volatile memory usually used for storing executable code. Some features, such as Storage Area Flash (SAF) or High Endurance Flash (HEF), can also use this section of memory to store data. However, modifying PFM is done per row rather than per byte.
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Program Flash Memory (PFM) | PFM is a non-volatile memory usually used for storing executable code. Some features, such as Storage Area Flash (SAF) or High Endurance Flash (HEF), can also use this section of memory to store data. However, modifying PFM is done per row rather than per byte.
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Data EEPROM
| Some MCUs contain dedicated data EEPROM memory, a type of non-volatile memory that you can erase and/or program on a per byte basis. This type of memory is a good option to store constants or data values.
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SRAM | SRAM is volatile memory for storing program variables or peripheral settings. |
Do You Need External Memory?
Serial Peripheral Interface (SPI), I2C and other serial interface EEPROMs are a cost-effective way to store large amounts of data.
Advanced Memory Features
Many of our MCUs have advanced memory features and peripherals that enable core-independent, low-cost and reliable designs. Please consult the device data sheet for feature availability in your MCU.
Storage Area Flash (SAF)
SAF is a feature of some MCUs that marks a section of PFM as non-executable memory. You can then use this section of memory for storing data or other values.
Self-Programming Capabilities
Many of our MCUs are capable of self-erase and self-programming capabilities for creating bootloaders and field upgradable firmware designs.
Code Protection
To protect your valuable intellectual property, the code protection features on the MCU can block attempts to read or edit the memory with a programmer or debugger. On PIC MCUs, this feature is known as “code protection” while AVR MCUs use the term “memory sections access protection”. For more information about this feature, please consult the device data sheet.
Read-While-Write Feature
Read-while-write is a feature found on some AVR® MCUs that allows for the CPU to continue executing while memory is being written. This feature only applies if the CPU is reading memory that is not in the read-while-write segment; see the device data sheet for more information.
Direct Memory Access (DMA)
DMA is a peripheral found on some PIC® MCUs that allows memory to be transferred from one location to another without using the CPU. Both hardware signals and software requests can initiate DMA transfers that range from a single byte to a large block of data.
Cyclic Redundancy Check (CRC)
CRCs are a common method for verifying the integrity of data or memory. A dedicated CRC peripheral can compute the CRC of a section of memory to verify that the memory has not been corrupted. For even higher reliability, some MCUs have a CRC-on-Boot peripheral to allow for memory verification before the MCU executes any software. CRC and CRC-on-Boot are commonly used in Functional Safety applications.
High-Endurance Flash (HEF)
On select MCUs, HEF memory is available in place of EEPROM. HEF is the first 128B of the PFM and it has a higher endurance than EEPROM with a rated endurance of 100,000 Erase/Write (E/W) cycles.
Storage Area Flash (SAF)
SAF is a feature of some MCUs that marks a section of PFM as non-executable memory. You can then use this section of memory for storing data or other values.
Self-Programming Capabilities
Many of our MCUs are capable of self-erase and self-programming capabilities for creating bootloaders and field upgradable firmware designs.
Code Protection
To protect your valuable intellectual property, the code protection features on the MCU can block attempts to read or edit the memory with a programmer or debugger. On PIC MCUs, this feature is known as “code protection” while AVR MCUs use the term “memory sections access protection”. For more information about this feature, please consult the device data sheet.
Read-While-Write Feature
Read-while-write is a feature found on some AVR® MCUs that allows for the CPU to continue executing while memory is being written. This feature only applies if the CPU is reading memory that is not in the read-while-write segment; see the device data sheet for more information.
Direct Memory Access (DMA)
DMA is a peripheral found on some PIC® MCUs that allows memory to be transferred from one location to another without using the CPU. Both hardware signals and software requests can initiate DMA transfers that range from a single byte to a large block of data.
Cyclic Redundancy Check (CRC)
CRCs are a common method for verifying the integrity of data or memory. A dedicated CRC peripheral can compute the CRC of a section of memory to verify that the memory has not been corrupted. For even higher reliability, some MCUs have a CRC-on-Boot peripheral to allow for memory verification before the MCU executes any software. CRC and CRC-on-Boot are commonly used in Functional Safety applications.
High-Endurance Flash (HEF)
On select MCUs, HEF memory is available in place of EEPROM. HEF is the first 128B of the PFM and it has a higher endurance than EEPROM with a rated endurance of 100,000 Erase/Write (E/W) cycles.
Storage Area Flash (SAF)
SAF is a feature of some MCUs that marks a section of PFM as non-executable memory. You can then use this section of memory for storing data or other values.
Self-Programming Capabilities
Many of our MCUs are capable of self-erase and self-programming capabilities for creating bootloaders and field upgradable firmware designs.
Code Protection
To protect your valuable intellectual property, the code protection features on the MCU can block attempts to read or edit the memory with a programmer or debugger. On PIC MCUs, this feature is known as “code protection” while AVR MCUs use the term “memory sections access protection”. For more information about this feature, please consult the device data sheet.
Read-While-Write Feature
Read-while-write is a feature found on some AVR® MCUs that allows for the CPU to continue executing while memory is being written. This feature only applies if the CPU is reading memory that is not in the read-while-write segment; see the device data sheet for more information.
