Add support PSRAM in ESP32, reduce memory usage and fix ethernet conn…

…ection issue in ESP32 core v2.0.0.

README.md

@@ -1,4 +1,4 @@
-# Mail Client Arduino Library v1.5.3
+# Mail Client Arduino Library v1.5.4
 
 
 [![Join the chat at https://gitter.im/mobizt/ESP_Mail_Client](https://badges.gitter.im/mobizt/ESP_Mail_Client.svg)](https://gitter.im/mobizt/ESP_Mail_Client?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
@@ -39,7 +39,7 @@ Copyright (c) 2021 K. Suwatchai (Mobizt).
 * Support the content decodings e.g. base64, UTF-8, UTF-7, quoted-printable, ISO-8859-1 (latin1) and ISO-8859-11 (Thai).
 * Support embedded contents e.g. inline images, attachments, parallel media attachments and RFC822 message.
 * Support full debuging.
-* Support flash memory (ESP32 and ESP8266), SD and SD_MMC (ESP32) for file storages which can be changed in [**ESP_Mail_FS.h**](/src/ESP_Mail_FS.h).
+* Support flash memory (ESP32 and ESP8266), SD and SD_MMC (ESP32) for file storages which can be changed in [**ESP_Mail_FS.h**](src/ESP_Mail_FS.h).
 * Support Ethernet (ESP32 using LAN8720, TLK110 and IP101 Ethernet modules, and ESP8266 (Arduino Core SDK v3.x.x and later) using ENC28J60, W5100 and W5500 Ethernet modules).
 * Customizable configurations (see the examples for the usages)
 
@@ -300,6 +300,28 @@ message.sender.email = email.c_str();
 ```
 
 
+### Use PSRAM on ESP32
+
+
+To enable PSRAM in ESP32 module with PSRAM chip, in Arduino IDE
+
+![Enable PSRAM in ESP32](/media/images/ESP32-PSRAM.png)
+
+
+In PlatformIO in VSCode IDE, add the following build_flags in your project's platformio.ini file
+
+```ini
+build_flags = -DBOARD_HAS_PSRAM -mfix-esp32-psram-cache-issue
+```
+
+The [**examples/SMTP/Send_Attachment_PSRAM/Send_Attachment_PSRAM.ino**](examples/SMTP/Send_Attachment_PSRAM/Send_Attachment_PSRAM.ino) showed how to send the attachment stored in PSRAM. 
+
+
+Since v1.5.4, this library supports PSRAM for internal memory allocation which you can config to use it via [**ESP_Mail_FS.h**](src/ESP_Mail_FS.h) with this macro.
+
+```cpp
+#define ESP_Mail_USE_PSRAM
+```
 
 
 ### Send the Email

library.json

@@ -1,6 +1,6 @@
 {
   "name": "ESP Mail Client",
-  "version": "1.5.3",
+  "version": "1.5.4",
   "keywords": "communication, email, imap, smtp, esp32, esp8266, samd, arduino",
   "description": "E-Mail Client Arduino Library that supports Espressif ESP32, ESP8266 and SAMD21 devices with built-in U-blox NINA-W102 module. This allows embedded devices to send, read Email, and get mailbox changes notification. The various types of content and attacment are supported.  The library also supports Ethernet connection (ESP8266 and ESP32) through secure (SSL) and non-secure ports.",
   "repository": {

library.properties

@@ -1,6 +1,6 @@
 name=ESP Mail Client
 
-version=1.5.3
+version=1.5.4
 
 author=Mobizt