Ferroelectric Memory Expansion for Firmware Updates

摘要

An integrated circuit including a ferroelectric random access memory (FRAM) for storing firmware, and a method of updating that firmware. The FRAM is constructed to selectively operate as a 2T2C FRAM memory in a normal operating mode, and as a 1T1C FRAM memory in an update mode. Updating of the stored firmware is performed by placing the FRAM in its update (1T1C) mode and writing the updated code into alternate rows of the 1T1C half-cells at each of a plurality of memory locations, while the other 1T1C half-cells in the other alternate rows retain the original data. Following verification of the updated contents, the original data in the other half-cells are overwritten with the verified updated data, and the operating mode is changed back to the normal (2T2C) operating mode.

主权项

1. A method of updating content stored in a ferroelectric random access memory (FRAM) array in an integrated circuit, the FRAM array including memory cells arranged in rows and columns, each memory cell of the FRAM array operable as two-transistor two-capacitor (2T2C) memory cells in a normal operating mode, and as first and second one-transistor one-capacitor (1T1C) half-cells in an update mode, the method comprising:
storing a first data set as complementary polarization states in each of a plurality of the memory cells; placing the FRAM array into the update mode; writing a second data set in the second half-cell of each of a selected plurality of the memory cells; verifying the second data set; responsive to successfully verifying the second data set, writing the second data set into the first half-cell of each of the selected plurality of memory cells; and then placing the FRAM array into the normal operating mode.