6 Configuration Mode Introduction
6.9 I2C Mode
UG290-2.5.2E
77(98)
Table 6-19 SERIAL Configuration Timing Parameters
Name
Description
Min.
Max.
T
sclkp
SCLK clock period
15ns
-
T
serials
SERIAL PORT setup time
2ns
-
T
serialh
SERIAL PORT hold time
0ns
-
T
readytsclk
Time from READY rising edge to first SCLK edge
TBD
-
Other than the power requirements, the following conditions need to
be met to use the SERIAL configuration mode:
SERIAL port enable
RECONFIG_N is not set as a GPIO during the first configuration after
power up or the previous programming.
Initiate new configuration
Power-on again or trigger RECONFIG_N at one low pulse.
6.9
I
2
C Mode
Note!
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.
In I
2
C Mode, Gowin FPGA products are configured by Host via I
2
C
interface. I
2
C Mode is one of the configuration modes that use the least
number of pins. The I
2
C mode can only write bitstream data to FPGA and
cannot readback data from FPGA devices; as such, the I
2
C mode cannot
read information on the ID CODE, USER CODE, status register and read
back check. A definition of the pins employed in the I
2
C mode is provided in
Table 6-20 Pin Definition in SERIAL Configuration Mode
Pin Name
I/O
Description
RECONFIG_N
I, internal
weak
pull-up
Low level pulse: Start GowinCONFIG
READY
I/O
High-level pulse: The device can be programmed
and configured;
Low level: Programming configuration for device
is prohibited
DONE
I/O
High-level: Successfully programmed and
configured;
Low-level: Programming and configuration
uncompleted or failed.
MODE[2:0]
I, internal
weak
pull-up
Configuration mode selection, READY rising edge
sampling
SCL
I
Input clock
SDA
I/O
Input data or output ACK
The connection diagram for the I
2
C mode is shown in Figure 6-55.