I'm using a Tower with Kinetis K65, and I managed some time ago to configure SDRAM and use it with not too much problems, but today I faced a very very strange issue.
Everything works fine when FTFE_FSEC is 0xFE, but when I change SEC bits to != 0b10, the device doesn't boots up.
Of course, under this circumstance I can't debug, as on-board flash is read-protected. After several tests, I found that when I disable the SDRAM initialization, the device works fine.
Anyone has seen something similar before? Can you give any indication of what can be wrong?
I have tested several combinations of FTFE_FSEC[SEC] bits. No positive results when flash external read is disbled.
This is my latest setting (in startup_MK65F18.S) :
/* Flash Configuration */
.section .FlashConfig, "a"
I'm using KDS with MQX. SDRAM configuration is done with ProcessorExpert (and it works fine when FTFE_FSEC[SEC] == 0b10)
Thank you in advance
EDIT: Device is able to boot (although SDRAM is not working) when I comment this two lines in SDRAM_Init.c
/* Write to an appropriate SDRAM address generates the pall command to the SDRAM block */
//*((uint8_t *)CS0_SDRAM_BASE_ADDRESS) = 0x00U;
/* Write access to the SDRAM address space generates the MRS command to that SDRAM */
//*((uint32_t *)CS0_MRS_COMMAND_ADDRESS) = 0x00000000U;
It seems that this two lines are attempting to write to SDRAM address, and I suspect that this is causing any kind of CPU fault.
It's very strange... when I set FTFE_FSEC[SEC] to 0b10 everything works just fine...