Memory read operation timed out, LCD and 1788
Does anybody have any idea where to look for this one? We have a custom LPC1788 design that has a TFT QVGA LCD and external sdram at 0xa0000000 - 0xa1ffffff.. If I point the LCD to external memory the debugger(Crosslink) will after about 15 seconds disconnect with the error "Memory read opration timed out." Here is the kicker if I disable the LCD it works just fine. Or if I point the display to internal memory all is good. Also there are other systems/code that use the external ram. So I am not sure if the ram is at fault. Also I did not have this problem with the Embedded Artist dev board using a Truly display. Our design uses a Tianma display. The debugger seems to work fine with the Truly timing and not the Tianma timing. One more weird point, the clock rate for the Tianma display is slower than the Truly, 6.4MHz vs 8.2MHz.
Some details
LCD used: Tianma TM035KDH03, chip Novatek NT39016D
CPU speed 120MHz, External bus 60MHz
Thanks,
Michael freeman
Update Systems, Inc
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I have a similar issue with a custom Atmel ARM SAM3U4E design. When RAM sections (e.g., bss, , .data, .stack) are placed in processor internal RAM, everything works. But when RAM sections are placed in external RAM starting at address 0x61000000, the debugger eventually disconnects with the error "Memory read operation timed out" or "Cannot write processor state". The software continues to run (i.e., it has not crashed) even though the debugger disconnected.
At this point, I don't know what's causing this issue.
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I ran into this issue too while trying to run long iterations on my EMC SRAM. Where I did a write to the SRAM by copying data over from Flash, then I did a modification in SRAM, which at this point of time ran into "Memory read operation timed out" or "Cannot write processor state". No real way to debug this because do not know where or what trip this particular condition. The only clue I got from my side is when I totally stop the SRAM pointer from moving will this problem stop occuring. Having said that, my SRAM pointer is only moving 16 bytes in the SRAM back and forth, continuing looping and not even going anyway further.
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