A programmable device (e.g., a programmable microcontroller) contains configuration registers which hold configuration data to establish functional blocks (e.g., which perform user-defined logic functions), I/O blocks (e.g., which configures input/output blocks interfacing to external devices), and/or signal routing resources (e.g., which connect the functional blocks to each other and/or the I/O blocks).
The configuration data may be represented as configuration bits of configuration registers (e.g., stored as volatile memory). Upon the boot-up of the programmable device, the configuration data stored in non-volatile memory may be copied to the configuration registers of the volatile memory. However, the configuration data residing in the configuration registers may be compromised due to several factors.
For example, an unintended software execution may create a write-over condition where improper data may be written to the configuration registers. Additionally, cosmic rays, X-rays, and/or other environmental factors may cause the configuration data to degrade (e.g., flip); these are known as soft errors. These errors (e.g., the write-over, soft errors, etc.) of the configuration data may compromise the functional block, the I/O blocks, and/or the routing resources, thereby rendering the programmable device inoperable for its intended purposes.
In case when the programmable device is used in a critical condition (e.g., involving an emergency situation) or life critical function, the reliability of the programmable device becomes ever more critical. For instance, the functionality of an airbag deployment system may rely on the operation of a programmable device. Furthermore, the configuration data (e.g., bits) become more susceptible to the soft errors as the feature size (e.g., a silicon geometry) of the programmable device gets smaller.