3 Configuration Modes
3.1 LittleBee® Family of FPGA Products
UG290-2.5.2E
6(98)
Table 3-1 Configuration Modes
Configuration Modes
MODE[2:0]
[1]
Description
JTAG
XXX
[2]
The LittleBee
®
Family of FPGA products
are configured via JTAG interface by
external Host.
GowinCONFIG
AUTO
BOOT
000
FPGA reads data from embedded Flash
for configuration
I
2
C
[6]
100
FPGA products are configured via I
2
C
interface by external Host.
SSPI
001
FPGA products of LittleBee
®
Family are
configured via SPI interface.
MSPI
010
As a Master, FPGA reads data from
external Flash (or other devices) via the
SPI interface
[3].
DUAL
BOOT
[4]
110
FPGA reads data from external Flash
first and if the external Flash
configuration fails, it reads from the
Internal Flash.
SERIAL
[5]
101
External Host configure FPGA products
of LittleBee
®
Family via DIN interface.
CPU
[5]
111
External Host configure FPGA products
of LittleBee
®
Family via DBUS interface.
Note!
[1] The unbound mode pins are grounded by default;
[2] The JTAG configuration mode is independent of MODE value;
[3] The SPI interfaces of the SSPI and MSPI modes are independent of each other;
[4] Currently GW1N(R)-4 / GW1N(R)-4B do not support DUAL BOOT;
[5] The CPU configuration mode and SERIAL configuration mode share SCLK,
WE_N and CLKHOLD_N. The data bus pins for the CPU configuration mode share
pins with MSPI and SSPI configuration modes.
[6] I
2
C is only supported in some devices. Autoboot is automatically enabled in I
2
C
mode. In I
2
C mode, following power-on the LittleBee devices will attempt to read data
from internal Flash first. The I
2
C SCL and SDA lines MUST be held inactive (pulled-up)
during Autoboot, otherwise the device maynot be configured correctly.
Note!
For details about configuration pins, pin reuse, and pin functions and application, please
refer to 5 Configuration Pin.