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boards/z80/ez80/z20x/README.txt: Update README.

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Gregory Nutt 2020-02-28 18:40:47 -06:00 committed by Abdelatif Guettouche
parent 43dfbdb348
commit e309128313
1 changed files with 25 additions and 7 deletions
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boards/z80/ez80/z20x/README.txt
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@ -95,6 +95,13 @@ Memory Constaints
you enable assertions, debug outputs, or even debug symbols. It is very
unlikely that the nsh_flash configuration will fit into FLASH at all!
I believe that there is some issue with the optimization CFLAGS used with
the ZDS-II compiler. The size of the FLASH images that are generated are
larger than you would see with, say, an equivalent Cortex-M compilation.
I reviewed the individual object files. There is not one thing that is
causing the large size. Rather, the ZDS-II compiler is simply generating
larger CODE sections in the object files.
Serial Console
==============
@ -212,12 +219,13 @@ Configuration Subdirectories
information see: apps/system/nsh/README.txt and
Documentation/NuttShell.html.
UNVERIFIED! I doubt that the nsh_flash program will fit into the
smaller FLASH memory of the eZ80F92 part.
NOTES:
1. The two configurations different only in that one builds for
1. UNVERIFIED! I doubt that the nsh_flash program will fit into the
smaller FLASH memory of the eZ80F92 part. See discusssion under
"Memory Constraints" above.
2. The two configurations different only in that one builds for
execution entirely from FLASH and the other for execution entirely
from RAM. A bootloader of some kind is required to support such
execution from RAM! This difference is reflected in a single
@ -237,7 +245,7 @@ Configuration Subdirectories
Why execute from SRAM at all? Because you will get MUCH better
performance because of the zero wait state SRAM implementation.
2. The eZ80 RTC, the procFS file system, and SD card support in included.
3. The eZ80 RTC, the procFS file system, and SD card support in included.
The procFS file system will be auto-mounted at /proc when the board
boots.
@ -304,7 +312,7 @@ Configuration Subdirectories
NOTE: The is no card detect signal so the microSD card must be
placed in the card slot before the system is started.
3. Debugging the RAM version
4. Debugging the RAM version
You can debug the all RAM version using ZDS-II as follows:
@ -315,7 +323,7 @@ Configuration Subdirectories
d. Single step a few times to make sure things look good, then
e. Go
4. Optimizations:
5. Optimizations:
- The stack sizes have not been tuned and, hence, are probably too
large.
@ -331,3 +339,13 @@ Configuration Subdirectories
SRAM.
The boot loader source is located at boards/z20x/src/sd_main.c.
NOTES:
1. This version of the eZ80 bootloader is not usable in its current
state. That is because the the eZ80F92 Interrupt Controller is
not as robust as the eZ80F91 Interrupt Controller. A consequence
is that the interrupt vectors must always reside within the first
64Kb of FLASH memory. It will not be possible to run programs in
SRAM *unless* some mechanism is developed to redirect interrupts
from ROM and into loaded SRAM logic.