SAME70 QSPI XIP Quad SPI External Flash Memory SMM Write Problem

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AfdhalAtiffTan
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Joined: Wed. Feb 22, 2017
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Posted by AfdhalAtiffTan: Mon. Feb 11, 2019 - 10:16 PM
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Hi all,

 

I am trying to write to a flash memory (S25FL064L) via QSPI, I have enabled SMM (serial memory mode) in the QSPI module. I use XIP (execute-in-place) example from Atmel Start.

 

I can read from it just fine, but when I try to write, my logic analyser shows that the SAME70 is appending at least 3 bytes per byte to the buffer, e.g. if I write 0x30, it will output 0x30, 0x20, 0xFF, 0xFF.

I tried to change the pointer type from uint8_t to uint32_t, it just made the matter worse.

 

The library access the flash memory via location 0x80000000 (SMM). Seems like this block from hpl_qspi.c is causing problem (dst is 0x80000000):

/**
 * \brief Memory copy function.
 *
 * \param dst  Pointer to destination buffer.
 * \param src  Pointer to source buffer.
 * \param count  Bytes to be copied.
 */
static void _qspi_memcpy(uint8_t *dst, uint8_t *src, uint32_t count)
{
	while (count--) {
		*dst++ = *src++;
	}
}

 

I have read an appnote: https://www.microchip.com/wwwApp...

 

It did mention about strongly ordered memory, but, I am not sure how to enable it using the APIs from Atmel Start.

 

Any ideas?

Tags:

Atmel SMART ARM-based MCUs and MPUs, Atmel Cortex-M MCUs
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AfdhalAtiffTan
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Joined: Wed. Feb 22, 2017
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Posted by AfdhalAtiffTan: Tue. Feb 12, 2019 - 03:07 PM
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The problem can be seen in the following logic analyser capture:

 

QSPI Issue

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AfdhalAtiffTan
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Posted by AfdhalAtiffTan: Thu. Feb 21, 2019 - 11:47 PM
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static void _qspi_memcpy(uint64_t *dst, uint64_t *src, uint32_t count)
{
	while (count--) {
		*dst++ = *src++;
	}
}

 

Well, I found a workaround, but, it is not pretty.

I can read in uint8_t, but, I can only write in uint64_t.

For consistency, I decided to do both read and write in uint64_t.

Basically, I just change both dst and src pointer type from uint8_t to uint64_t.

This will allow me to only read/write in 8-byte chunks. Not ideal, but, it will do for now.

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