Configuration areas¶
MiraOS features memory areas for configuring application and hardware. Userconfig, sysconfig, and certificate are such memory areas.
These memory areas share a common format.
Area types¶
Userconfig¶
Use the userconfig area to store application specific data in non-volatile memory. The application may use this area through the configuration API.
The production line may also flash user data into this memory area.
The linker script area CONFIG1 sets the location of the userconfig in memory.
Sysconfig¶
The sysconfig area stores hardware related configuration.
Location
| Chip | Location | Size |
|---|---|---|
| nrf52832_XXAA | NRFUICR->CUSTOMER[0..31] (0x10001080) |
128 bytes |
| nrf52840_XXAA | NRFUICR->CUSTOMER[0..31] (0x10001080) |
128 bytes |
| mkw41z512 | Not implemented |
Resilience
Updates of application firmware versions in flash should typically not overwrite the sysconfig area. Modify the content of the sysconfig area only when modifying the hardware.
Certificate¶
The certificate area stores the unit's license to run MiraOS.
Format¶
The configuration areas share a common format:
| data fields | type | version | CRC |
|---|---|---|---|
| variable size | 16 bits | 16 bits | 32 bits |
Fields are stored as little endian.
Data fields¶
Userconfig
Format of the fields in userconfig are at the discretion of the user.
Sysconfig
The only currently supported setting is module ID, in the first uint32_t of
the sysconfig area.
Module ID
| value | module name |
|---|---|
| 0 | unknown |
| 1 | Bare nRF52832_XXAA |
| 2 | Bare nRF52840_XXAA |
| 3 | Bare mkw41z512 |
| 4 | LumenRadio MLE N2 |
| 5 | LumenRadio MWA N2 |
| 0x4000 | Custom 0 |
| 0x4001 | Custom 1 |
| 0x4002 | Custom 2 |
| 0x4003 | Custom 3 |
Unrecognized values such as 0xffffffff load the "unknown" configuration by default.
Certificate
The format of the certificate memory area is not public. Unused area must be padded with 0xff.
Type¶
The second to last uint32_t of the format stores the configuration type in its
least significant uint16_t.
| value | Area type |
|---|---|
| 0 | undefined |
| 1 | userconfig |
| 2 | sysconfig |
| 3 | certificate |
Version¶
The second to last uint32_t of the format stores the format version in its
most significant uint16_t. Versioning the format is important in order to read
older configurations with new firmware.
CRC¶
The last uint32_t of the area stores the IEEE 802.3 CRC32 of the preceding area.
Content example¶
As an example, the content of the sysconfig area for a unit configured as a custom module 0 is:
0x10001080: 00 40 00 00 FF FF FF FF FF FF FF FF FF FF FF FF
0x10001090: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x100010A0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x100010B0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x100010C0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x100010D0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x100010E0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x100010F0: FF FF FF FF FF FF FF FF 02 00 00 00 1B D1 73 D9
00 40 00 00 is the module type for custom module 0 (0x00004000 in little endian).
02 00 is the configuration area type (2 is sysconfig).
00 00 is the configuration format version.
The last four bytes 1B D1 73 D9 are the CRC-32.