I have a project using a CY8C6x4 processor (CY8C6247FDI-D32). We have a requirement to service an interrupt on the M4 core at a very high rate (~ eve...
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I have a project using a CY8C6x4 processor (CY8C6247FDI-D32). We have a requirement to service an interrupt on the M4 core at a very high rate (~ every 640us). We also have a requirement to write to flash memory using the M0 core while this interrupt is running. The M0 and M4 cores are running from flash in sector U1 (0x10040000) and the flash being written is U3 (0x100C0000). Below are a bunch of questions related to writing to flash using "partial blocking" methods.
Looking at the PSoC Peripheral Driver Library Flash Section (link) you can use partial blocking methods to try to keep the "non-flashing" core running while doing a flash erase and a flash write. The documentation has Figure 1 which shows some general timing for the StartErase() + StartProgram() method and the StartWrite() method. I have tried both and it looks like both processors get "locked" for a period of time.
Figure 1 has a Legend that shows "Available to read from flash", "Busy with SRM code (CM0+)", and "Blocking-out SRAM". I can figure out what (and see from my traces) what the first two mean. What I don't understand is what does "Blocking-out in SRAM" mean? Does this mean the processor can't execute from SRAM? Also what are the implications of this time period?
I'm trying to get something useful done on the M4 during the "Blocking-out in SRAM" period. From what I can see from traces I have collected is that there isn't much the M4 can do while the M0 is "starting the erase" and "starting the program". The code that I'm running is not getting interrupts during this period. So are both processors blocking in an NMI interrupt? Are interrupts disabled on both processors?
I understand that the M0 is tied up working with SROM and IPC during these times. I also understand that at least on the M0 a critical section cannot be entered. Is that true for the M4 as well? It the M4 locked up on IPC during these times as well?
I'm wondering if I can execute SRAM code on the M4 during this "Blocking-out in SRAM", but it isn't clear to me what blocking-out means. Also I'm not sure why I can't use Flash during this time since the sectors I'm using should be isolated. I have dug into the CY code that is interfacing with the SROM/IPC and it is running in SRAM (so that it is not using the flash or the flash cache).
Any help on this would be greatly appreciated and I suspect others would like to have a better understanding of what is going on while the SROM code is executing.
Best Regards,
Lenny
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