Hi e2e,
Our customer meet a problem in TM4C129LNCZAD with external SDRAM(EPI bus) using as the LCD graphic buffer, they system is working as below described;
1. External SDRAM is using as LCD graphic buffer, and also used for user application buffer at the same time;
2. LCD module will read graphic buffer via DMA regularly;
3. MCU will have burst R/W to SDRAM in some condition, it will occupy EPI bus at this time, if the EPI bus is hold for a long time, LCD underflow interrupt will generate a lot;
4. sometimes the LCD module still work fine while some LCD underflow interrupt generated, but if the interrupt is too much in a short time, the LCD module won't work anymore, it means it can not recover and transmit data from SDRAM to LCD module in DMA, LCD display will be in abnormal with mass color in display, and finally going to white;
they also did a test to easily repeat the issue, if they put the system heap into SDRAM, the issue will repeat frequently, and currently they are putting the heap in internal SRAM.
Do you have any suggestion in their application? and is there any way to keep the LCD module alive even there are many LCD underflow interrupt generated.
thanks.
LEON