Update README

This commit is contained in:
Gregory Nutt 2015-11-13 15:56:16 -06:00
parent dae831b7ba
commit 06b48e5152

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@ -577,15 +577,18 @@ D-Cache must be configured in write-through mode:
CONFIG_ARMV7M_DCACHE_WRITETHROUGH=y CONFIG_ARMV7M_DCACHE_WRITETHROUGH=y
The total FLASH is organized as 128KB/sector x 16 sectors = 2MB. The The total FLASH on the SAMV71 is organized as 128KB/sector x 16 sectors
sectors are all uniform (except for sector zero which will never be used = 2MB. The sectors are all uniform (except for sector zero which will
by the driver). never be used by the driver).
In this configuration I have aside 8 sectors, or 8 * 128KB = 1MB of the The configuration sets aside 8 sectors, or 8 * 128KB = 1MB of the FLASH
FLASH for testing. Ideally, one should also modify the linker script and for programmable memory (CONFIG_SAMV7_PROGMEM_NSECTORS=8). The exact
reduce the size of the available FLASH by 1MB in this case to avoid number of sectors set aside is optional.
difficult run-time problems. I did not do that because I know that my
test program is small. NOTE: Ideally, one should also modify the linker script and reduce the size
of the available FLASH the amount set aside for program usage to avoid
difficult run-time problems. That would be 1MB in this configuration. I
did not do that only because I know that my test program is small.
When the system boots, you can see the FLASH driver: When the system boots, you can see the FLASH driver:
@ -610,7 +613,7 @@ of 16 pages or 8KB. In the code, I you will see that I refer to these
groups of 16 pages as "clusters." So the cluster is the smallest thing groups of 16 pages as "clusters." So the cluster is the smallest thing
that you can perform a read/write/modify operation on. that you can perform a read/write/modify operation on.
I am using 8 sectors = 16 *8 = 128 clusters (aka blocks). You can see Using 8 sectors yields 16 *8 = 128 clusters (aka blocks). You can see
this when the apps/examples/media test runs: this when the apps/examples/media test runs:
nsh> media nsh> media
@ -635,6 +638,12 @@ this when the apps/examples/media test runs:
Re-read/Verify: Block 127 Re-read/Verify: Block 127
nsh> nsh>
NOTE: The media test can be added to the NSH configuration with:
CONFIG_EXAMPLES_MEDIA=y
CONFIG_EXAMPLES_MEDIA_BLOCKSIZE=8192
CONFIG_EXAMPLES_MEDIA_DEVPATH="/dev/mtd1"
Networking Networking
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