This is the Linux BSP (Board Support Package) for the Emcraft Systems STM32F4 System-On-Module (SOM) Starter Kit.
The BSP provides a software development environment for evaluation and development of Linux (uClinux) on the Cortex-M4 processor core of the STM32F4 microcontroller using the Emcraft Systems STM32F4 SOM Starter Kit as a hardware platform.
The following list summarizes the features and capabilities of this release of the STM32F4 SOM Starter Kit BSP:
- Kernel v4.2;
- Serial Linux console;
- Ethernet device driver and Linux TCP/IP networking (ping, NFS, Telnet, FTP, NTPD, etc);
- WiFi connectivity with security;
- PPP-based TCP/IP connectivity over GSM/3G modems;
- Bluetooth support using bluez;
- busybox v1.17;
- POSIX pthreads;
- Hardened exception handling; an exception triggered by a process affects only the offending process;
- Loadable kernel modules;
- Secure shell (ssh) and secure copy (scp);
- Web server;
- MTD-based Flash partitioning and persistent Flash file system in external Flash;
- Multi-port serial UART driver;
- USB Host and Device (widget) device drivers for both the USB HS (High Speed) and USB FS (Full Speed) interfaces;
- SD Card device driver;
- I2C master-mode device driver;
- SPI master-mode device driver;
- GPIO device driver.
- U-Boot firmware:
- U-Boot v2010.03;
- Target initialization from power-on / reset;
- Runs from the internal eNVM and internal SRAM (no external memory required for standalone operation);
- Serial console;
- Ethernet driver for loading images to the target;
- Device driver for built-in Flash (eNVM) and self-upgrade capability;
- Device driver for storing environment and Linux images in external Flash;
- Autoboot feature, allowing boot of OS images from Flash or other storage with no operator intervention;
- Persistent environment in Flash for customization of target operation;
- Sophisticated command interface for maintenance and development of the target.
- Development tools:
- Linux-hosted cross-development environment;
- ARMv7-optimized GNU toolchain from CodeSourcery (2010q1) is used for development of U-Boot, Linux and user-space applications (toolchain must be downloaded separately from the CodeSourcery web site);
- Cross GDB for debugging user-space applications;
- Integration with Eclipse IDE;
- mkimage tool used by the Linux kernel build process to create a bootable Linux image.
New and Changed Features
This section lists new and changed features of this release:
- Move STM32F4 SOM to Linux kernel v.4.2.
ID: RM 137.
- Merge inittab in uClinux.
ID: RM 139.
- Create consolidated rootfs project for STM32F4 SOM.
ID: RM 142.
- Merge Emcraft exception-handling code into the baseline kernel.
ID: RM 149.
- Port SFTP to uClinux.
ID: RM 205.
- Support USB device (gadget) in linux-4.2.
ID: RM 259.
- Allow debugging user-space applications using Eclipse IDE.
ID: RM 262.
- Enable and validate I2C, SPI, SD Card, UART, GPIO, USB FS/HS Host/Target.
ID: RM 272.
- Enable bluez in the rootfs project for STM32F4 SOM.
ID: RM 275.
- Add scp and ssh clients.
ID: RM 305.
- Enable support for USB WiFi in rootfs.
ID: RM 308.
- Support PPP over USB modem.
ID: RM 342.
Known Problems & Limitations
This section lists known problems and limitations of this release:
- JTAG debugging rates are limited to 1 KHz.
ID: RT 101140.
Workaround: If you require running JTAG at higher frequencies, interrupt the Linux autoboot sequence by resetting the target and pressing any key on the serial console, thus entering the U-Boot command line interface. The Linux kernel is configured to enter a low-power mode by executing a wfi instructions whenever the system enters the so called idle loop (there are no active tasks to execute), which interferes with running JTAG at high-rate frequencies.