Fanstel BlueFan BT680E, Manual, Page: 16 / 30

BlueFan BT680F/E/T BLE5 Module
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In host mode, BlueFan module communicates commands, status, and data with a host CPU through
UART interfaces. The UART interfaces are shared with GPIO pins, and during boot process after a
reset, module firmware assigns UART functions to the GPIOs.
Flow Control Function
BlueFan module UART interface uses flow control function by hardware signal, Transmit flow control
(CTSX) and receive flow control (RTSX). Above Figure shows signals input and
output direction .
CTSX input signal is used for UART transmitting. Low input indicates close of the preparation of the
other party to receive data and module executes UART transmitting data if there is data for
transmission. In case of input high level, module stops transmitting
by UART frame.
RTSX input signal is used for UART receiving. Low output indicates request data transmission to
UART transmitside device of the other party. module outputs Low level from RTSX when being able
to receive data and prepares to receive data.Response time of UART transmitting and receiving for
flow control signal depends on baud rate and internal process status of frame. It is from 1 frame to 4
frames.
Response time of UART transmitting and receiving for flow control signal depends on baud rate and
internal process status of frame. It is from 1 frame to 4 frame.
Error Detect Function
Module
UART interface has 3 kinds of error functions.
•
Receiver timeout error
•
Receiver over run error
•
Receiver frame error
Receiver timeout error reports as an error if the receiver frame interval counted by internal timer is
equal to or greater than a predetermined time
Receiver over run error is reported if UART internal receive frame buffer isoverflowed.
Receiver frame error is reported if it fails to recognize the unit frame.
SPI Interface
Features SPI interface.
•
Utilize VDDIO power supply

SPI interface:
▪
Chip select: 2 channels
▪
Chip select polarity: High-active, Low-active
▪
Serial clock master operation: Polarity and phase are adjustable
▪
Serial clock frequency: 8 kHz to 16 MHz
▪
Serial data transfer mode: MSB-first or LSB first
I
2
C interface
Features of I 2 C interface
•
Utilize VDDIO power supply