11
Flash Memory
The Pico E‐14 comes equipped with at least 64 megabytes of Flash ROM. The Flash ROM is divided into 512 sectors that can be erased independently. Most of the space on the ROM is reserved for the user.
The Flash ROM’s address bus can be controlled by either the TurboLoader or the FPGA, but not both. During power‐up or reboot, the TurboLoader is in control of the Flash ROM Address bus. At all other times the FPGA is in control of the address bus.
Figure 2
Typical Flash ROM Allocation Table:
Byte addresses | Description | Flash Sectors |
0x00000000‐0x0000FFFF | Tuple Data and configuration management | 0 |
0x00010000‐0x0006FFFF | Primary FPGA Image | 1‐6 |
0x000A0000‐0x000FFFFF | Backup FPGA Image | 7‐12 |
0x000D0000‐0x0012FFFF | Secondary Image including boot loader | 13‐19 |
0x00140000‐0x01FFFFFF | Other FPGA images, executables and data files | 20‐511 |
The Flash ROM has a simple, open file system that allows the user to store FPGA images, ELF binary files, or other data. The primary image is used to boot the FPGA initially, and the backup image is only invoked if the primary image fails to load correctly. Executable files are in ELF format and are loaded by a loader within the secondary image. The primary image can either load the secondary image or pause for the PC to access and manage the file system.
E‐14 Hardware Reference Manual | www.picocomputing.com | Pico Computing, Inc. |
