A1: Helloworld is blinking LED lights. You cannot see the screen output anything. That's correct. If you want to see something from the screen, you may need to refer to the examples about Graphic_xxx.
Q2: Current flash storage on LinkIt Assist 2502 is limited to 4 MB, which is not sufficient. How to connect a SD card to LinkIt Assist?
A2: Linkit Assist 2502 does not have a provision for SD card and the Linkit Assist 2502 SDK (firmware) also does not enable/support SD card interface. These are available in LinkiIt One. We suggest you to use the internal memory for storage or transfer the data to remote server periodically. Linkit Assist 2502 is a co-designed product with MediaTek. The SDK and features are provided by MediaTek. For further questions on this topic, please contact MediaTek Forums.
Q3: LinkIt Assist has an exchangeable 240X240 capacitive touch LCM board. Is it possible to support a higher resolution, like 320x320?
A3: The SoC used MT2502A supports LCD upto 320x240. Please see the documentation here.
Q4: Does this support Touch panel input without external hardware?
A4: It does not. You can use a touch panel with I2C. MT2502A supports I2C. The driver/software to implement touch functions has to be developed for your specific module.
Q5: I tried Graphic_loadfont and Audio_Play, but there is no response from LCD and Speaker.
A5: Here is the sequence for playing with this board in case of failure or error:
a. Connect battery to Linkit Assist board