I am buy EVB LPC54S018M-EVK with LPC54S018 and connect to it SPI-MRAM chip = MR25H40.
I need to load the firmware into LPC54S018 from SPI-MRAM (MR25H40). I connected the MRAM to FLEXCOMM9. I can read and write of data to this MRAM from my firmware normally - it ok. But I can't boot of MCU from it.
On the oscillogramm, I see that (after RESET) the microcontroller's boot-ROM code begins communicating with the MRAM at the default speed = 12 MHz (boot-ROM sending it a wake-up command (opcode = 0xAB) and then three times sending a "read JEDEC-ID" command (opcode = 0x9F)). After that, no further activity occurs on the SPI. The wake-up command is processed normally by the MRAM, but the "read JEDEC-ID" command is not supported by the memory (according to the datasheet by MRAM). I thought that the boot-ROM code, having not received a response to the "read JEDEC-ID" command, would simply continue booting at the default speed. But for unknown reason, after three attempts to "read JEDEC-ID", the boot process is cancelled.
I tried setting the ISP pins of LPC54S018 to the following states:
1) or ISP0 = high, ISP1 = high, ISP2 = high;
2) or ISP0 = high, ISP1 = low, ISP2 = high.
Nothing changes - the microcontroller won't boot.
Is there any way to continue booting of LPC54S018 from SPI-memory without waiting for a response to the "read JEDEC-ID" command?
PS: I am attaching oscillograms of the loading process.
