Hello Habr! This article describes the development process of a Wireless Sensor Network (WSN) gateway for transmitting data from wireless sensors to a server via mobile communication. We will use Sub-1GHz SoC CC1310 and WP8548 programmable module from Sierra Wireless as filling. AirPrime WP8548 is an industrial LGA-239 module. Its wireless modem provides data transmission in HSPA, WCDMA, EDGE and GPRS networks, as well as GPS signal reception.
Motivation. Why is this all?
Of course, this problem could be solved by using the CC1310 microcontroller in conjunction with a 3G modem from SIMCOM or Quectel, but: the WP8548 module has been in my desk for several years. I never found a rational application of this module because of its cost ($ 60, DigiKey ), but the itch to try it in practice still torments me. I warn you right away:
The solution is more expensive than similar ones from Aliexpress
I am not solving a specific problem, but trying to assess the capabilities of this module
Step 1. Power block diagram
The most boring stage of designing a circuit of a future device. But put all our sighs aside and see the power parameters of the main components of the circuit. Opening page 26 of the documentation and see that the WP8548 supply voltage range is from 3.4 to 4.3 volts (it suggests power from a lithium battery). The CC1310 operates on a supply voltage of 1.8 to 3.8 volts. Let's present general requirements for the future device:
Work from a lithium battery + charging it
5V step-up converter for powering external devices from a lithium battery.
The ability to power off a part of the circuit when going into sleep mode
PCB size is no larger than a credit card, of course
, . WP8548 MicroSD , 2,95 . GPIO 1.8, . , 1.8 3.3. HSIC . USB3503 ( LDO) USB .
BQ24292. 17 , 12 . 4, PowerBank' 20.
TPS63802. 6 , 2 ( ) buck-boost .
CC1310 PMIC, 3.3 . .
:
1.8 ()
3.3 ()
2.95 MicroSD ()
3.3 CC1310 ( )
(ADJ) TPS79301 , .
:
2. .
, . .
17. USB ( PSEL +VBUS), BQ24292 , USB .
U5 U10 . WP8548 0 PWR_ON, pull-up . , VT1 VT2 . Open-drain CC1310 .
MicroSD, CC1310, USB
USB WP8548, ESD .
3:
. , keep-out. .
. , . , SMD . , - , .
. .
3D .
. , . , , .
, , . , DC-DC c 12 5. , . 5 2.8 . , . , .
/ . , , .
. - :) , - , - . , COM-.
. 192.168.2.2
, SSH . root, .
, SIM- , .
, . CC1310 .