5 Configuration Mode Introduction
5.6 DUAL BOOT Configuration (Supported by LittleBee®
Family Only)
UG290-2.3E
63(87)
Note!
In DUAL BOOT mode, when the external Flash is empty or non-existent, FPGA will try to
read data from the built-in Flash.
The specific MODE value needs to be selected for the DUAL BOOT
MODE. No external connection is required for the built-in Flash. The
connection diagram for reading from external Flash is the same as that of
the MSPI mode. Please refer to Figure 5-40. In Dual BOOT mode, users
can select where to save the configuration data required.
The Dual BOOT mode supported by GW1NS-2/GW1NS-2C device is
slightly different from that of the other LittleBee
®
family devices.
GW1NS-2/GW1NS-2C has double built-in Flash, so
GW1NS-2/GW1NS-2C switches between the two built-in Flash in Dual
BOOT mode.
The Dual Boot mode configuration flow is shown in Figure 5-47.
Figure 5-47 Dual Boot Flow Chart
start
ready
?
emFlash
fail
?
exFlash
fail
?
Y
N
Y
end
N
fail
success
Y
N
Note!
When the MODE value is set to "110", the FPGA first attempts to configure from the
external Flash.
GW1N(R)-9 and GW1NS series products support four times
configuration in all DUAL BOOT modes.
Start from the preferred storage path and attempt three times; if all
attempts fail, start from the other storage path. The embedded Flash
can only be started at “0“ address;
When the MODE value is "110", different startup addresses can be
selected for the three attempts to start from external Flash. The startup
address needs to be written to the bitstream through Gowin software in
advance. If the configuration fails three times, the devices attempt to
start from the built-in Flash.
The GW1NS series of FPGA products support multiple restarts after
failures, but the start address cannot be modified.