HF-BL200A Low Energy Bluetooh
(
BLE 4.1
)
Module User Manual
Shanghai High Flying Electronics Technology Co., Ltd www.hi-flying.com
- 18
-
Remark
:
user can set particular communication mode according to actual application, packet
length can be set between 80byte < L < 200byte
,
the relationship as below as per BLE protocol:
If L<80
,
TS >= T
;
If 80<L<160
,
TS >= T*2
;
If 160<L<200
,
TS >= T*3
;
All transmit mode is safe as long as it meets above conditions, TS=T is recommended,
TS=T*2
,
TS=T*3 is ok but the packet lost ratio is high, must add verification and re-transmit
mechanism. In another words, if apply 80byte < L < 200byte ,serial data can transmit to module in one
time, but need to reserve time for sending data from module to Bluetooth, or there will occur rear-end.
E.g. Set connect interval T=20ms, if data length is L=200, TS must over T*3 = 60ms , TS=70ms is a
reasonable choice.
Serial data length can be any value under 200 byte. In order to achieve the best efficiency and
avoid full load operation , it is recommended to use 20,40,60 byte serial data packet, set packet
interval over 20ms.
Remark
:
in IOS, the function is used to call Characteristic is:
BCharacteristicWriteWithRespons
e parameter,
“write with response” mode would lower transmit efficiency to ensure the accuracy
of each packet. Using
“ CBCharacteristicWriteWithoutResponse” ; “write without response” mode
would promote transmit efficiency , but the accuracy of packet need to be verified by APP up level.
3.2.
Transparent Transmit Mode Pin Description
All pins of Transparent Transmit
:
UART_TX
、
UART_RX
、
WAKEUP
、
BCTS
、
XRES
、
MANUFACTURE
Min. pins of Transparent Transmit
:
UART_TX
、
UART_RX
、
WAKEUP
Details refer to
《
Appendix A
》
WEAKEUP: inside high impedance, pin must be connected. Pull up to stop UART receive
function. UART is unable to receive data (UART able to send data). Pull down to enable UART to
receive data.
MANUFACTURE: Pull down inside, and it can be no connection. Pull up outside and power on or
reset, keep high level MANUFACTURE at least 5 second. Module restore factory setting
XRES: Pull up inside, can be no connection
BCTS: In normal time, output low level; BCTS output high level before sending data from module,
after sending , BCTS output low level.