6.1.5 Flash Memory Programming

The Flash Controller (FC) works with panels made from 4 KB pages, with each page containing four rows of Flash data. A row is the largest selectable region for contiguous programming of write words. The number of write words in a row varies based on write word width. See the following figure.

Except for the JTAG Test Mode (TMOD12), the FC does not know about the other test modes. The FC state machine accepts commands from the NVMCON register NVMOP commands (NVMCON.NVMOP) in both the Mission mode and the Test Mode.

A page of Flash is the smallest unit of memory that can be erased in a single operation. A panel’s program Flash space is the only other unit that can be erased in a single operation. All other erases use multiple operations either autonomously by the FC or by software.

A write word is the only unit of memory that can be programmed at a time. All other programming operations are comprised of several contiguous write word program events.

The FC supports the following functions:
  • Row Programming – Word-by-word programming until the whole row is programmed; the FC reads the data from the system SRAM
  • Quad Programming – The FC performs four writes of data from holding registers
  • Single Programming – The FC performs one write of data from holding registers
  • Page Erase with FC
  • Chip Erase with DSU
Figure 6-1. 128-Bit Wide Flash Module Application View

Small Flash memories support simple boot loaders and have eight total NVR pages (seven available for the user). The NVMOTP page is the highest user accessible page in the NVR region. NVMOTP is mapped to page NVMOTP_PAGE.

The NVMOTP page is always erase-protected by hardware. The associated LBWP[] and UBWP[] allow writes to the page(s) when logic ‘0’, and prevent writes when logic ‘1’.
Figure 6-2. 128-Bit Wide Flash Module