2.5.1.4.9 SPI Flash Boot

Two types of SPI Flash are supported: SPI Serial Flash and SPI DataFlash.

The ROM code tries to boot on SPI, first looking for SPI Serial Flash, and then for SPI DataFlash.

It uses the analysis of Arm exception vectors to detect a valid bootstrap code.

The SPI Flash read is done by means of a “Continuous Read” command from address 0x0. This command is 0xE8 for DataFlash devices and 0x0B for Serial Flash devices.

Supported DataFlash Devices

The ROM code supports the DataFlash devices listed in the following table.

Table 2-13. DataFlash Devices
DeviceDensityPage Size (bytes)Number of Pages
AT45DB0111 Mbit264512
AT45DB0212 Mbits2641024
AT45DB0414 Mbits2642048
AT45DB0818 Mbits2644096
AT45DB16116 Mbits5284096
AT45DB32132 Mbits5288192
AT45DB64264 Mbits10568192
AT45DB64164 Mbits26437768

Supported Serial Flash Devices

The ROM code supports all SPI Serial Flash devices responding correctly to both “Get Status” and “Continuous Read” standard commands.