6 Bitstream File Configuration
UG290-2.3E
80(87)
Both LittleBee
®
family and Arora family of GOWINSEMI FPGA devices
support MSPI mode, that is, after the device is powered on, it can read
bitstream files from the external SPI Flash and then
complete the configuration. The default frequency of reading configuration
file is 2.5 MHz. One bit is read at each SPI clock, so the required loading
time can be calculated according to the file size. The clock frequency of
reading SPI Flash in MSPI mode can be up to 125 MHz. Note that the
FastRead_n pin should be grounded at the same time when Fast Read SPI
(
0x0B
)
is used.
The LittleBee
®
family devices support not only MSPI mode, but also
Autoboot mode. The loading frequency is 2.5 MHz by default, and Autoboot
mode loads one byte (8 bits) per clock. The loading time varies depending
on the configuration file size, load frequency, and per-clock loading width.
Due to the different process of the embedded Flash, the maximum
Autoboot loading frequency for different devices is also different. The
specific maximum loading speed is as shown in Table 6-2 below.
Table 6-2 Loading Frequency of Config File
Device
Max. Loading Frequency of
Autoboot
Max. Loading Frequency of
MSPI
GW2A-55/55C
–
125 MHz
GW2A-18/18C
GW2AR-18/18C
GW2ANR-18C
GW1N-1
26 MHz
GW1N-1S
GW1NS-2
33 MHz
120 MHz
GW1NSR-2
GW1NS-2C
GW1NSR-2C
GW1NSE-2C
GW1NZ-1
40 MHz
GW1N-2