AN4683 datasheet(23/31 Pages) STMICROELECTRONICS

23 / 31 page

DocID027745 Rev 1

23/31

AN4683

Demonstration package

The first step is to open the secure connection to the HTTPS server: it is recommended to

run AT+S.TLSCERT2=clean,all to clean the Flash memory and then open a secure

connection to hostname my.st.com on port 443 as below. Note that the parameter ind is

enabled to activate asynchronous indications of pending data from the server.

AT+S.SOCKON=my.st.com,443,s,ind<CR>

ID: 00<CR><LF>

When the TLS Handshake is successful, the AT+S.SOCKON gives back the sock id and all

the data exchanged from now on are encrypted with the newly established session key.

The second step is to send an HTTPS message to the server: the following code shows how

to use the AT+S.SOCKW to send a basic HTTP GET request:

AT+S.SOCKW=00,18<CR>

GET / HTTP/1.1<CR><LF>

The server response to the above GET request is signaled by a couple of asynchronous

indications (see the WIND:55 in the box below). In order to get and decrypt the received

data, we have to iteratively call AT+S.SOCKQ and AT+S.SOCKR to process all the received

pending data as follows:

+WIND:55:Pending Data:0:ENC<CR><LF>

+WIND:55:Pending Data:0:ENC<CR><LF>

AT+S.SOCKQ=00<CR>

DATALEN: 483<CR><LF>

AT+S.SOCKR=00,483<CR>

HTTP/1.1 302 Found<CR><LF>

Date: Tue, 31 Mar 2015 08:48:16 GMT<CR><LF>

Location: https://my.st.com/cas/login?service=https://my.st.com/<CR><LF>

Content-Length: 238<CR><LF>

Content-Type: text/html; charset=iso-8859-1<CR><LF>

Proxy-Connection: Keep-Alive<CR><LF>

Connection: Keep-Alive<CR><LF>

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><LF>

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