README ====== This directory contains the port of NuttX to the Beaglebone Black board See http://beagleboard.org for information about Beaglebone Black. This board is based around the TI AM335x Sitara Cortex-A8 CPU. This port was developed on the rev. C of the board: Beaglebone Black (See http://beagleboard.org/black) ITEMS DETAILS -------------------- --------------------------------------------------- CPU 1GHz ARM Cortex-A8 GPU SG530 3D, 20M Polygons/S DRAM 512MB DDR3 800MHz Onboard Storage 4GB, 8bit Embedded MMC, microSD card (TF) slot for up to 32GB Video Output HDMI Extension Interface 2.54mm Headers, 92 pins Network interface 10/100Mbps RJ45 Power 5V, 1000mA Overall Size 3.4" X 2.15" Main features of the TI AM335x Sitara (See http://www.ti.com/product/am3358): CPU - ARM Cortex-A8 - 32KB I-Cache - 32KB D-Cache - 256KB L2 Cache with ECC FPU - NEON SIMD Coprocessor Memory - 176KB of On-Chip Boot ROM - 64KB of Dedicated RAM - 64KB of General-Purpose On-Chip Memory Controller (OCMC) RAM - 16-bit DDR2/DDR3 - Memory capacity up to 8G bits - 8-Bit and 16-Bit Asynchronous Memory Interface with up to Seven Chip Selects (NAND, NOR, Muxed-NOR, SRAM) Boot Devices - NAND Flash - SPI NOR Flash - SD Card - UART TODO: Contents ======== - Beaglebone black Rev.C Connectors - Serial Console - LEDs - Buttons - JTAG - Booting NuttX from an SD card - Configurations Beaglebone black Rev.C Connectors ===================== Serial Console ============== By default, the serial console will be provided on UART0 in all of these configurations. UART0 is available on the 6-pin Debug connector: Pin 1: GND Pin 2: N/C Pin 3: N/C Pin 4: B_UART0_RX / UART0_RX / PIN E15 Pin 5: B_UART0_TX / UART0_TX / PIN E16 Pin 6: N/C PIN E16: UART0_TXD/SPI1_CS1/DCAN0_RX/I2C2_SCL/ECAP1_IN_PWM1_OUT/ PR1_PRU1_PRU_R30_15/PR1_PRU1_PRU_R31_15/GPIO1_11 PIN E15: UART0_RXD/SPI1_CS0/DCAN0_TX/I2C2_SDA/ECAP2_IN_PWM2_OUT/ PR1_PRU1_PRU_R30_14/PR1_PRU1_PRU_R31_14/GPIO1_10 LEDs ==== The Beaglebone black Rev. C has four blue LEDs; three can be controlled from software. Two are tied to ground and, hence, illuminated by driving the output pins to a high value: 1. LED0 GPMC_A5 GPMC_A5/GMII2_TXD0/RGMII2_TD0/RMII2_TXD0/GPMC_A21/ PR1_MII1_RXD3/eQEP1B_IN/GPIO1_21 2. LED1 GPMC_A6 GPMC_A6/GMII2_TXCLK/RGMII2_TCLK/MMC2_DAT4/GPMC_A22/ PR1_MII1_RXD2/eQEP1_INDEX/GPIO1_22 3. LED2 GPMC_A7 GPMC_A7/GMII2_RXCLK/RGMII2_RCLK/MMC2_DAT5/GPMC_A23/ PR1_MII1_RXD1/eQEP1_STROBE/GPIO1_23 4. LED3 GPMC_A8 GPMC_A8/GMII2_RXD3/RGMII2_RD3/MMC2_DAT6/GPMC_A24/ PR1_MII1_RXD0/MCASP0_ACLKX/GPIO1_24 These LEDs are not used by the board port unless CONFIG_ARCH_LEDS is defined. In that case, the usage by the board port is defined in include/board.h and src/am335x_leds.c. The LEDs are used to encode OS-related events as follows: SYMBOL Meaning LED state LED1 LED3 LED4 ----------------- ----------------------- ---- ---- ------------ LED_STARTED NuttX has been started ON OFF OFF LED_HEAPALLOCATE Heap has been allocated OFF ON OFF LED_IRQSENABLED Interrupts enabled ON ON OFF LED_STACKCREATED Idle stack created ON ON OFF LED_INIRQ In an interrupt N/C N/C Soft glow LED_SIGNAL In a signal handler N/C N/C Soft glow LED_ASSERTION An assertion failed N/C N/C Soft glow LED_PANIC The system has crashed N/C N/C 2Hz Flashing LED_IDLE MCU is is sleep mode Not used After booting, LED1 and 3 are not longer used by the system and can be used for other purposes by the application (Of course, all LEDs are available to the application if CONFIG_ARCH_LEDS is not defined. Buttons ======= JTAG ==== Booting NuttX from an SD card ============================= These are the steps to get U-Boot booting from SD Card: 1. Configure and build the NuttX Beaglebone Black configuration. You should have a file alled nuttx.bin when the build completes. 2. Insert a FLASH stick into the host PC and format it for FAT32 FS. 3. Copy nuttx.bin into FLASH stick root. 4. Remove the FLASH stick from the host PC. Insert into the Beaglebone Black microSD slot. 5. Connect a RS-232 Converted or USB serial adapter onto the Beaglebone Black board and open a serial terminal on the host PC to communicate with the target. 6. Reset the Stop Beaglebone Black boot. You should see output from U-boot in the serial console. Stop the normal boot-up sequence after the U-Boot prompt before Linux is started.: Hit any key to stop autoboot: 0 U-Boot# 7. Load Nuttx into memory from the U-Boot prompt and run U-Boot# load mmc 0 0x8a000000 nuttx.bin U-Boot# go 0x8a000000 If your are running the 'nsh' configuration you then should see: NuttShell (NSH) nsh> Configurations ============== Information Common to All Configurations ---------------------------------------- Each Beaglebone Black configuration is maintained in a sub-directory and can be selected as follow: tools/configure.sh [OPTIONS] beaglebone-black/ Where [OPTIONS] include -l to configure for a Linux host platform and -c means to configure for a Windows Cygwin host platform. -h will give you the list of all options. Before building, make sure the PATH environment variable includes the correct path to the directory than holds your toolchain binaries. And then build NuttX by simply typing the following. At the conclusion of the make, the nuttx binary will reside in an ELF file called, simply, nuttx. make The that is provided above as an argument to the tools/configure.sh must be is one of the following. NOTES: 1. These configurations use the mconf-based configuration tool. To change any of these configurations using that tool, you should: a. Build and install the kconfig-mconf tool. See nuttx/README.txt see additional README.txt files in the NuttX tools repository. b. Execute 'make menuconfig' in nuttx/ in order to start the reconfiguration process. 2. Unless stated otherwise, all configurations generate console output on UART0. 3. All of these configurations use the Code Sourcery for Windows toolchain (unless stated otherwise in the description of the configuration). That toolchain selection can easily be reconfigured using 'make menuconfig'. Here are the relevant current settings: Build Setup: CONFIG_HOST_WINDOWS=y : Microsoft Windows CONFIG_WINDOWS_CYGWIN=y : Using Cygwin or other POSIX environment System Type -> Toolchain: CONFIG_ARMV7A_TOOLCHAIN_CODESOURCERYW=y : CodeSourcery for Windows Configuration Sub-directories ----------------------------- nsh: This configuration directory provide the NuttShell (NSH). There are STATUS: 2019-01-06: Work in progress. Till now it is possible to pass arm_boot(), but Prefetch abort is met when devnull_register() call is done. Have no idea why. I was able to trace down to _inode_search() call. If I put any debug statement like "up_lowputc('0');" right after "desc->node = node;" statement at line 425 the code does not crash. 2019-01-09: The NSH configuration is now functional. 2019-01-16: Correct timer interrupts by switching to DMTimer2 (DMTimer1ms is not initialized by U-Boot).