First stage: planning of bootloader

A project log for Redphone

The Redphone project is an open source mobile phone

Vasilii ChumakovVasilii Chumakov 06/25/2019 at 13:072 Comments

Bootloader must be written in internal STM32 flash memory. It is no OS bare metal program with simple utils for system control and execute main firmware in SDRAM (based on FreeRTOS or linux).

Implementation plan (July - August):

1. Fix issue with my china usb->uart based on cp2102 (need to re solder chip)

2. Develop VT100 terminal emulator for supporting utils executing (with direct calls main routines of application)

3. Develop compact dynamic memory allocator in SDRAM (maybe based on FreeRTOS model 4 allocator)

4. Adding support of my FAT32 FS driver (supporting only read operation)

4.b. Realization loader of binary files from SD card. Led blink test program.

5. Write utils for control:

5.1. FAT FS file system (ls, cat, rm, du)

5.2. i2c devices (read, write and search devices on i2c bus)

5.3. power controller (enable/disable phases, set up and check voltages)

5.4. boot nand of FPGA (write/read/verify operations)

5.5. frame buffer and LTDC module configuration (util must load BMP pictures from SD card and showing it on LCD)

6. Program booting NAND flash of ESP8266 (maybe need to re solder chip on PCB for connect it to NodeMCU devkit)

7. Write basic util for GSM modem control (init, get rssi/snr/status, make calls)

8. Write basic util for control of ESP8266 (init, connect to AP, show list of APs), be called as "wctl"

9. Upgrade FAT32 FS for supporting write operations (same add cp util)

10. Upgrade "wctl" for download files from FTP to SD card

11. ELF loader (September)


colton.baldridge wrote 06/27/2019 at 17:32 point

Wow, I'm excited to see how this turns out. Please post more updates as you go along.

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Vasilii Chumakov wrote 06/28/2019 at 12:02 point

Thank you for your interest!

No problems! I will try to write more about each paragraph.
Perhaps I will done a simple virtual terminal for stm32 already on Sunday.
By the way, today I fixed my console cp2102)

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