189 lines
4.1 KiB
Plaintext
189 lines
4.1 KiB
Plaintext
Consideration about SYS and the first pages of flash ROM
|
|
========================================================
|
|
|
|
Now, I'm developing something like SYS for Kinetis L MCU, so, I write
|
|
this document.
|
|
|
|
|
|
About SYS on STM32F103
|
|
======================
|
|
|
|
In the development of Gnuk, we developed:
|
|
|
|
SYS: The system predefined routines for STM32F103
|
|
|
|
It is now maintained as example-cdc/sys.c.
|
|
|
|
There is another version in example-led/sys.c, which also support
|
|
STM32F030, as well as STM32F103. But, it wouldn't be useful for
|
|
STM32F030. In fact, the file example-fsm-55/sys.c has name sys.c
|
|
but it doesn't include any system routines.
|
|
|
|
The original issue was:
|
|
|
|
(1) When it's protected, STM32F103 can't change the first 4KiB of
|
|
flash ROM at run time.
|
|
|
|
(2) We want to support firmware upgrade through its USB.
|
|
|
|
Later on, we add another point.
|
|
|
|
(3) It is good if the executable of Gnuk could be shared among
|
|
different boards.
|
|
|
|
For (1) and (2), we decided put some useful routines and data which is
|
|
not need to be changed.
|
|
|
|
Now, the first 4KiB of flash ROM consists of:
|
|
|
|
1KiB: SYS
|
|
3KiB: 3/4 of AES forward tables
|
|
|
|
SYS consists of:
|
|
|
|
Internal: reset entry, end of RAM
|
|
Data: board identification
|
|
Routines: board specific
|
|
board independent
|
|
|
|
and here is the list of all.
|
|
|
|
* Internal routines
|
|
|
|
reset entry
|
|
end of RAM
|
|
|
|
* Board identification
|
|
|
|
sys_version
|
|
sys_board_id
|
|
sys_board_name
|
|
|
|
* Board specific routines
|
|
|
|
* led
|
|
set_led
|
|
|
|
* mcu/board lower level
|
|
clock_init
|
|
gpio_init
|
|
|
|
* usb
|
|
usb_lld_sys_init
|
|
usb_lld_sys_shutdown
|
|
|
|
* Board independent routines
|
|
|
|
* flash ROM access routines
|
|
|
|
unlock
|
|
write halfword
|
|
erase page
|
|
brank check
|
|
write page
|
|
protect
|
|
erase_all & exec to ram
|
|
|
|
* system reset routine
|
|
|
|
nvic_system_reset
|
|
|
|
The routines of clock_init and gpio_init are here because of some
|
|
historical reasons. (We could design a system with no such exported
|
|
routines: by defining: those things done internally after reset and
|
|
before calling the application.)
|
|
|
|
Those are exported as entries of SYS, and it is the responsibility of
|
|
the application which do initialize clock and GPIO, calling those
|
|
routines.
|
|
|
|
USB routines are needed because of hardware practice of STM32F103.
|
|
With STM32F103, each board has different way for handling the pull up
|
|
of USB D+ and how the device asks re-enumeration to host PC. In my
|
|
opinion, if it's defined as full speed device and it's OK for us not
|
|
to use high impedance (but asserting to LOW, instead) of D+ to ask
|
|
re-enumeration, we can just pull up D+ always. And we wouldn't need
|
|
such routines in SYS.
|
|
|
|
|
|
|
|
About SYS on Kinetis L
|
|
======================
|
|
|
|
For Kinetis L, because it's ROM has the original firmware upgrade
|
|
support by the vendor (though USB HID), all that we needed for
|
|
firmware upgrade would be just erasing to factory settings.
|
|
|
|
And it has no limitation like STM32F103's first 4KiB flash ROM.
|
|
All pages can be updated at run time.
|
|
|
|
Nevertheless, the first two pages (2KiB) of KL27Z is still difficult
|
|
to use.
|
|
|
|
So, I decide to introduce something like SYS for Kinetis L.
|
|
|
|
|
|
* Layout
|
|
|
|
Three pages (3KiB) usage:
|
|
|
|
------------ The first page
|
|
End of RAM <-- not used but hardware defines this
|
|
Address of reset entry
|
|
sys_version
|
|
sys_board_info (id, name)
|
|
sys_vector
|
|
|
|
other SYS routines and data...
|
|
|
|
------------ The second page
|
|
FLASH CONFIG: 16-byte
|
|
Reset entry function
|
|
flash routines
|
|
CRC-32 routines
|
|
CRC-32 table (768-byte of CRC-32 table)
|
|
|
|
------------ The third page
|
|
MAGIC 256-byte (256-byte of the last part of CRC-32 table)
|
|
...
|
|
vectors (initial MSP, reset, ...)
|
|
...
|
|
|
|
|
|
* data: Board identification
|
|
|
|
sys_version
|
|
sys_board_id
|
|
sys_board_name ; null terminated
|
|
|
|
* Board specific routines
|
|
|
|
* mcu/board lower level
|
|
clock_init
|
|
gpio_init
|
|
|
|
* led
|
|
set_led
|
|
|
|
* data: Board independent routines
|
|
|
|
* flash ROM access code to be loaded on to RAM
|
|
|
|
* system reset routine???
|
|
|
|
nvic_system_reset
|
|
|
|
|
|
* data: vectors for routines and data
|
|
sys_version
|
|
sys_board_id
|
|
address of sys_board_name
|
|
address of set_led
|
|
address of clock_init
|
|
address of gpio_init
|
|
address of ...
|
|
|
|
|
|
|
|
--
|