circuitpython/ports/esp8266/boards/esp8266_1m.ld

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esp8266: Change from FAT to littlefs v2 as default filesystem. This commit changes the esp8266 boards to use littlefs v2 as the filesystem, rather than FAT. Since the esp8266 doesn't expose the filesystem to the PC over USB there's no strong reason to keep it as FAT. Littlefs is smaller in code size, is more efficient in use of flash to store data, is resilient over power failure, and using it saves about 4k of heap RAM, which can now be used for other things. This is a backwards incompatible change because all existing esp8266 boards will need to update their filesystem after installing new firmware (eg backup old files, install firmware, restore files to new filesystem). As part of this commit the memory layout of the default board (GENERIC) has changed. It now allocates all 1M of memory-mapped flash to the firmware, so the filesystem area starts at the 2M point. This is done to allow more frozen bytecode to be stored in the 1M of memory-mapped flash. This requires an esp8266 module with 2M or more of flash to work, so a new board called GENERIC_1M is added which has the old memory-mapping (but still changed to use littlefs for the filesystem). In summary there are now 3 esp8266 board definitions: - GENERIC_512K: for 512k modules, doesn't have a filesystem. - GENERIC_1M: for 1M modules, 572k for firmware+frozen code, 396k for filesystem (littlefs). - GENERIC: for 2M (or greater) modules, 968k for firmware+frozen code, 1M+ for filesystem (littlefs), FAT driver also included in firmware for use on, eg, external SD cards.
2020-03-26 07:35:32 -04:00
/* GNU linker script for ESP8266 with 1M flash
Flash layout:
0x40200000 36k header + iram/dram init
0x40209000 572k firmware (irom0)
0x40298000 396k filesystem
0x402fb000 20k SDK parameters
*/
MEMORY
{
dport0_0_seg : org = 0x3ff00000, len = 16
dram0_0_seg : org = 0x3ffe8000, len = 80K
iram1_0_seg : org = 0x40100000, len = 32K
irom0_0_seg : org = 0x40209000, len = 572K
}
/* define common sections and symbols */
INCLUDE boards/esp8266_common.ld