ESP8266_RTOS_SDK pre-release 2.0.0-rc1

System

1. Memory optimization
   1.1. Support puting .rodata into flash, with modifications of ld file;
   1.2. Modify to use 16KB Cache mode, and the saved 16KB iRAM are used as heap region;
2. Update to use heap_5.c from FreeRTOS, support multi heap pools;
3. Update boot to version 1.7:
   3.1. boot currently use bin 3 times，if all fail, turn to boot the bin of last user;
   3.2. Support 8MB & 16MB SPI Flash;
4. Update ld file, put .rodata in some libs to SPI Flash by default;
5. Add gcc flag -fno-jump-tables to reduce .rodata usage;
6. Support eon SPI Flash, dio -> qio mode;
7. Support 8MB & 16MB SPI flash；
8. Remove mesh support;
9. Use gcc to compile all libs;
10. Show stack info when exception occur;
11. Improve dio -> qio function of some SPI Flash;
12. Modify rom ld, export some low level functions;
13. Fix some os_ macro;
14. Fix deep sleep crash issue;
15. Fix wdt crash issue in some cases;

Driver

1. Fix the issue of hw_timer;
2. Fix the issue of SPI tx/rx data sometimes wrong；
3. Fix the issue of setting UART flow control；

Examples

1. Add websocket demo;
2. Add wifi_station_machine_demo;
3. Add openssl server demo；
4. Add openssl client demo；
5. Add mqtt demo；

Protocol

Lwip

1. Add dhcp options;
2. Enable ETHARP_TRUST_IP_MAC in lwipopt.h;
3. Modify dhcp/dhcps timer from 60 seconds to 1 second;
4. Remove time() function in lwip;
5. Rebind UDP pcb when IP changed;
6. Fix the error of socket macro definition;
7. Fix the connection issue of multi-clients;
8. Fix the issue of containing more than one tcp pbuf in single tx packet;
9. Fix lwip slow timer delay more than one second;
10. Fix mss_local is always subtract the IPv6 header size;
11. Fix multi-thread issues;

espconn

1. Add source codes of espconn;

mbedTLS

1. Fix ECP memory leak;

OpenSSL

1. Add openssl wrap layer;

MQTT

1. Add phao mqtt support;

WiFi

1. Update libphy to version 1055_1;
2. Save PMK to SPI flash, improve the station connect speed;
3. Modify scan API, support to scan more info.;
4. Add the description of vendor IE API;
5. Add beacon & probe response freq IE;
6. Add the support of CSA;
7. Add WiFi station keep alive support;
8. Add passive & active scan support;
9. Add country code APIs;
10. Add support of packets forward in softAP mode;
11. Fix the bug of mic failure handler;
12. Fix the issue of group key update;
13. Fix WPA/WPA2 PTK/GTK; reinstallation vulnerability;
14. Fix the bug of scan hidden AP;
15. Fix some potential memory leak;
16. Fix WiFi tx/rx status wrong which will cause LmacRxBlk:0 error;
17. Fix WDT when call espnow delete;