Add support for the STM32G474 family of microcontrollers and the
B-G474E-DPOW1 Discovery Board, which features a STM32G474RET6.
This is a major pull request as it adds support for an entirely
new family of STM32. This support is implemented in
arch/arm/src/stm32 and shares implementation with other STM32
families supported by that code, such as the 'L15xx, 'F10xx,
'F20xx, 'F3xxx, and 'F4xxx.
arch/arm/Kconfig:
arch/arm/include/stm32/chip.h:
arch/arm/include/stm32/irq.h:
arch/arm/src/stm32/Kconfig:
arch/arm/src/stm32/hardware/stm32_adc.h:
arch/arm/src/stm32/hardware/stm32_adc_v2.h:
arch/arm/src/stm32/hardware/stm32_dma.h:
arch/arm/src/stm32/hardware/stm32_dma_v1.h:
arch/arm/src/stm32/hardware/stm32_flash.h:
arch/arm/src/stm32/hardware/stm32_i2c.h:
arch/arm/src/stm32/hardware/stm32_i2c_v2.h:
arch/arm/src/stm32/hardware/stm32_memorymap.h:
arch/arm/src/stm32/hardware/stm32_pinmap.h:
arch/arm/src/stm32/hardware/stm32_tim.h:
arch/arm/src/stm32/stm32_allocateheap.c:
arch/arm/src/stm32/stm32_dma.c:
arch/arm/src/stm32/stm32_dma_v1.c:
arch/arm/src/stm32/stm32_dumpgpio.c:
arch/arm/src/stm32/stm32_gpio.c:
arch/arm/src/stm32/stm32_gpio.h:
arch/arm/src/stm32/stm32_lowputc.c:
arch/arm/src/stm32/stm32_rcc.c:
arch/arm/src/stm32/stm32_rcc.h:
arch/arm/src/stm32/stm32_serial.c:
arch/arm/src/stm32/stm32_syscfg.h:
arch/arm/src/stm32/stm32_uart.h:
* Add architectural support to existing NuttX files. This
makes the STM32G474 family parts accessible to the system.
With big thanks for detailed code review:
David Sidrane (davids5)
Mateusz Szafoni (raiden00)
Abdelatif Guettouche (Ouss4)
1. Add dsp extension; float point based on hardware and software.
2. Delete folder "iar"
3. Add tool chain for cortex-M23 and cortex-M35p
Signed-off-by: qiaowei <qiaowei@xiaomi.com>
Change-Id: I5bfc78abb025adb0ad4fae37e2b444915f477fe7
Spresense smp
* arch: arm: Add ARCH_GLOBAL_IRQDISABLE to ARCH_CHIP_CXD56XX in Kconfig
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* arch: arm: cxd56xx: Make fpuconfg() public in cxd56_start.c
NOTE: fpuconfig() is called in both cxd56_start.c and cxd56_cpustart.c
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* arch: arm: cxd56xx: Add support for SMP
NOTE: To run cxd56xx in SMP mode, new boot loader which will be
released later must be used.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* arch: arm: cxd56xx: Add irq routing for SMP in cxd56_irq.c
NOTE: In cxd56xx, each external interrupt controller can be
accessed from a local APP_DSP (Cortex-M4F) only. This commit
supports IRQ routing for SMP by calling up_send_irqreq() in
both up_enable_irq() and up_disable_irq().
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* boards: spresense: Add smp configuration
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
Approved-by: Gregory Nutt <gnutt@nuttx.org>
Move boards to boards folder
* boards: rename configs folder to boards
This is the proposed layout after the change:
boards: - folder containing board folders
<board>: - name of each board
drivers: - extra drivers specific for platform
include: - header files for the boars
scripts: - extra scripts specific for platform
src: - board specific code
tools: - extra tools specific for platform
<config>: - board specific configuration(s)
Note:
<xxx> names are dependent on platform
This is a logical change to aim to the arch layout but this is a
huge change it should be done in several steps to lower the risk.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* Kconfig: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* Makefile: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* Makefile.*: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* Make.defs: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* .sh: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* .mk: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* .c & .h: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
* .bat: replace configs with boards
The change is needed after the path change
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
Approved-by: Gregory Nutt <gnutt@nuttx.org>
Add support for LPC40xx family chips
* Corrected a few peripheral definitions and pin functions for the LPC17xx family.
Added configuration options, chip definitions, and additional pin functions for the LPC40xx family.
Added board configurations for Embedded Artists LPC4088 Quickstart board and LPC4088 Developer's kit. These configurations are still something of a work in progress. In particular, the LCD functionality is untested.
* First pass rename in *.c and *.h files.
* Renamed LPC17XX to LPC17XX_40XX in config files
* Rplaced LPC17xx with LPC17xx/LPC40xx in .c files
* Replaced LPC17xx with LPC17xx/LPC40xx in .h files
* Updated some documentation
* Working on moving directories
* moved arch/arm/src/lpc17xx and arch/arm/include/lpc17xx to lpc17xx_40xx
* Renamed LPC17_* constants / configuration options to LPC17_40_*
* Updated chip family name defines
* Renamed some chip-specific files
* Updated references to renamed files
* Updated references to lpc17_ to lpc17_40_
* Renamed source files from lpc17_* to lpc17_40_*
* Clean up white space
Approved-by: Gregory Nutt <gnutt@nuttx.org>
Squashed commit of the following:
arch/arm: Rename include/stm32f0l0 and src/stm32f0l0 to stm32f0l0g0.
Change all occurrences of lower-case stm32f0l0 to stm32f0l0g0.
Change all occurrences of upper-case STM32F0L0 to STM32F0L0G0.
libs/libc/pthread/pthread_spinlock.c: Resolve several TODO issues by accessing up_testset() via the boardctl() interface rather than attempting to call it directly.
configs/boardctl.c, include/sys/boardctl.h: Add access to architecture-specific up_testset() via boardctl().
arch/Kconfig's, sched/Kconfig, and include/nuttx/spinlock.h: Spinlocks are not available unless the architecture supports the up_testset() operation.
arch/arm/src/tiva/hardware: Add CC13xx SMPH and AUX SMPH header files. Still need DDI0 OSC header file for CC13x0 compilation.
arch/arm/src/tiva/cc13xx: A few changes toward getting the launchxl-cc1310/nsh configuration to build
Squashed commit of the following:
Author: Gregory Nutt <gnutt@nuttx.org>
Many small changes related to coding style.
Author: Petro Karashchenko <petro.karashchenko@gmail.com>
configs/beaglebone-black: Adds initial support for the BeagleBone Black board.
arch/arm/src/am335x: Adds initial support for the TI AM355x family.
Squashed commit of the following:
arch/arm/src/stm32f0l0: Various changes for a clean compilation. Still does not compile correctly due to missing FLASH latency definitions.
arch/arm/src/stm32f0l0/hardware: Add framework for the STM32 L0. Currently set to same as the STM32F0.
arch/arm/src/stm32f0l0/hardware: Very fragmentary FLASH header register definitions for the STM32 L0.
arch/arm/src/stm32f0l0: Bring in DMA v1. Cannot possibly be functionaly yet due to the limited number for M0 interrupts.
arch/arm/src/stm32f0l0: Add STM32 F0/L0 LSE and backup power domain controls.
arch/arm/src/stm32f0l0/hardware/stm32l0_pwr.h: Add STM32L0 PWR header file.
arch/arm/include/stm32f0l0/chip.h: Clean up WIP chip header file.
arch/arm/include/stm32f0l0/chip.h: WIP.
arm/src/stm32f0l0: Resolve some small differences between F0 and L0 GPIO pin options.
arch/arm/src/stm32f0l0: Better integrate STM32L0 header files.
nuttx/arch/arm/include/stm32f0l0: Add STM32L0 IRQ number definition file.
arch/arm/src/stm32f0l0: Add STM32L0 RCC driver.
arch/arm/src/stm32f0l0/hardware: Adds basic STM32L0 header files.
arch/arm/src/stm32f0l0: Add STM32L0 chip selections.
configs/: Hook new STM32L0 boards into the configuration system.
configs: nucleo boards use as default ST LINK MCO as clock input from MCU and for this HSEBYP must be enabled
configs: add basic support for nucleo-l073rz
configs: add basic support for b-l072z-lrwan1
arch/arm/src/stm32f0l0: Some fixes for a clean build. Still have a problem with lots of error messages coming from kconfig-mconf, but the configuation looks fine. Sometimes kconfig errors are difficult to spot. I would appreciate it anyone can spot the issue.
arch/arm/src/stm32f0l0/hardware: Rename the chip directory to hardware. This will hopefully eliminate some problems that I have seen with the chip include paths not being unique in more complex configuartions.
configs/nucleo-f072rb, configs/nucleo-f091rc, configs/stm32f051-discovery, and configs/stm32f072-discovery: Update for all of the naming changes made in arch/arm/src/stm32f0l0
arch/arm/include/stm32f0l0: Rename stm32f0 to stm32f0l0 to make a speace for STM32 L0. Rename files, functions and defines, removeing the f0_ from the names in order to make them MCU agnostic.
arch/arm/src/stm32f0l0: Rename stm32f0 to stm32f0l0 to make a speace for STM32 L0. Rename files, functions and defines, removeing the f0_ from the names in order to make them MCU agnostic.
arch/arm/src/tiva/hardwar: Move LM3S and LM4F include files to hardware/lm/ sub-directory. Move all TM4C header files files to hardware/tm4c/ sub-directory.
arch/arm: Add basic configuration/build support for CC13xx parts. Conditioned on EXPERIMENTAL.
This update is required to be serialized to the instruction stream meaning that after this update completes, it takes effect immediately and no exceptions of lower priority than the new boosted priority can pre-empt execution. Because of this erratum, the priority boosting does not take place immediately, allowing the instruction after the MSR to be interrupted by an exception of lower priority than the new boosted priority. This effect is only limited to the next instruction. Subsequent instructions are guaranteed to see the new boosted priority.
This was raised in Bitbucket issue 113 from Vadzim Dambrouski.
Squashed commit of the following:
arch/arm/src/samd5e5: Clean-up EIC logic.
arch/arm/src/samd5e5: Fix some compilation issues; Still issues with the EIC logic from samd2x.
arch/arm/src/samd5e5: Fix some compilation issues; bring in some EIC logic from samd2x.
arch/arm/src/samd5e5: Add NVMCTRL header file, fix some compiler problems, misc. clean-up.
configs/metro-m4: Add LED support.
arch/arm/src/samd5e5: Bring in SAML21 clock configuration. This is a WIP; it cannot possible even compile yet.
arch/arm/src/samd5e5: Leverage Cortex-M4 interrupt and SysTick logic from the SAM3/4.
arch/arm/src/samd5e5: Add SERCOM utility function.
arch/arm/src/samd5e5: Bring all SERCOM USART logic from SAMD2L2 to SAMD5E5. This is a brute coy with nothing more than more that name changes and extension from 5 to 7 SERCOMs.
arch/arm/src/samd5e5: Add sam_config.h header file
arch/arm/src/samd5e5/: Add Generic Clock (GCLK) utility functions.
arch/arm/src/samd5e5: Add EVSYS register definition file
arch/arm/src/samd5e5 and configs/metro-m4: Use SERCOM3 for the Arduino serial shield as console.
arch/arm/src/samd5e5/chip: Add SERCOM USART, SPI, I2C master, and slave register defintions header files
arch/arm/src/samd5e5/chip: Add AES, PM, TRNG, and WDT header files.
arch/arm/src/samd5e5/chip: Add pin multiplexing header files.
Various fixes to configuration system; fix metro-m4/nsh defconfig file.
configs/metro-m4: Add initial support for the Adafruit Metro M4 board.
arch/arm/src/samd5e5: Add peripheral clock helpers.
arch/arm/src/samd5e5/chip: Add PAC register definition header file. Fix some errors in the memory map header file.
arch/arm/src/samd5e5: Add chip.h headerf file.
arch/arm/src/samd5e5: Add PORT register definitions and support from SAML21.
arch/arm/include/samd5e5: Add interrupt vector definitions.
arch/arm/src/samd5e5: Add some boilerplate files. Correct some typos.
arch/arm/src/samd5e5/chip/sam_eic.h: Add EIC register definitions.
arch/arm/src/samd5e5/chip: Add OSC32KCTRL and OSCCTRL register definitions.
arch/arm/src/samd5e5/chip: Add GCLK, MCLK, and RSTC header files.
arch/arm/src/samd5e5/chip/sam_cmcc.h: Add CMCC register definitions
arch/arm/src/samd5e5/chip/sam_supc.h: Add SUPC header file.
arch/arm/src/samd5e5: Add start-up logic.
arch/arm/src/samd5e5: Add Make.defs file
arch/arm/src/samd5e5/chip: Add memory map header file.
arch/arm/include/samd5e5: Add chip.h header file.
arch/arm/Kconfig and arch/arm/src/samd5e5/Kconfig: Add configuration logic for the SAMD5x/Ex family.
Squashed commit of the following:
Change all remaining occurrences of SAMDL to SAMD2L2.
configs/: Change all remaining occurrences of SAMDL to SAMD2L2
configs/: Change all occurrences of CONFIG_SAMDL_* to CONFIG_SAMD2L2_*
arch/arm/src and include: Rename all directories from samdl to samd2l2. Change all configuration variable names and other usage from SAMDL to SAMD2L2.
arch/arm: Remove support for CONFIG_ARMV7M_CMNVECTOR. It is now the only vector support available. Also remove CONFIG_HAVE_CMNVECTOR. That no longer signifies anything."
arch/arm/src/stm32: This commit removes support for the dedicated vector handling from the STM32 architecture support. Only common vectors are now supported.
arch/arm/src/lpc17xx: This commit removes support for the dedicated vector handling from the LPC17xx architectures. Only common vectors are now supported.
arch/arm/src/kinetis: This commit removes support for the dedicated vector handling from the Kinetis architectures. Only common vectors are now supported.
Squashed commit of the following:
arch/arm/src/kinetis: A fixes from first (unsuccessful) attempt to build the Freedom-K28F configuration.
configs/freedom-k28f: Add basic board support for Freedom-K28F. Initial commit is basically just the Teensy-3.x brought up to date and with name changes.
This port was the joing effort of Janne Rosberg, Ivan Ucherdzhiev, and myself. I give credit to Ivan for the kill because he is the one to held on to the end.
Squashed commit of the following:
Author: Gregory Nutt <gnutt@nuttx.org>
configs/imxrt1050-evk/scripts: Add section to linker script to handle the case where RAMFUNCs are enabled. RAMFUNCs appear to be enabled in the default configuration ... they probably should not be enabled.
Author: Ivan Ucherdzhiev <ivanucherdjiev@gmail.com>
arch/arm/src/imxrt: imxrt_lowputc.c is finished. Now everything needed for the initial port is done and ready for testing.
arch/arm/src/imxrt: Add logic to imxrt_lowputc.c. Still incomplete.
Author: Ivan Ucherdzhiev <ivanucherdjiev@gmail.com>
arch/arm/src/imxrt: Add serial support. configs/imxrt1050-evk: Add linker script.
Author: Gregory Nutt <gnutt@nuttx.org>
arch/arm/src/imxrt: Add initial cut at imxrt_allocateheap.c
Author: Ivan Ucherdzhiev <ivanucherdjiev@gmail.com>
arm/arm/src/imxrt: Completes all definitions for PADMUX, CTLMUX, and IOMUX_INPUT and mapping tables on imxrt_gpio.c and imxr_iomuxc.c.
arch/arm/src/imxrt/chip: Add definitions for IMXRT_PADCTL and IMXRT_PADMUX registers. Only the IMXRT_INPUT definitions in this commit.
arch/arm/src/imxrt/chip: Add more IOMUXC register definitions.
Author: Gregory Nutt <gnutt@nuttx.org>
configs/imxrt1050-evk: Add STRIP definition to Make.defs.
arch/arm/src/imxrt: Bring in i.MX6 memory configuration settings.
arch/arm/src/imxrt: Remove call to non-existent imxrt_gpioinit() from imxrt_start.c.
arch/arm/src/imxrt: Bring in incomplete imxrt_iomuxc.c file from i.mx6.
arch/arm/src/imxrt: Add first cut at GPIO interrupt logic.
arch/arm/include: Add definitions to support a second level of GPIO pin interrupts.
Author: Janne Rosberg <janne.rosberg@offcode.fi>
arch/arm/src/imxrt: Add imxrt_wdog.c/.h
Author: Gregory Nutt <gnutt@nuttx.org>
arch/arm/src/imxrt: Port SAMv7 interrupt logic to imxrt_irq.c.
arch/arm/src/imxrt: More clarification of the start-up memory map.
arch/arm/src/imxrt: Some mostly cosmetic clean-up to the imxrt_start.c file that was so rudely taken from the SAMv7.
arch/arm/src/imxrt: Add imxrt_start.c. Initial commit is the the SAMv7 startup logic with name changes.
Author: Ivan Ucherdzhiev <ivanucherdjiev@gmail.com>
arch/arm/src/imxrt: Adds a few IOMUXC register definitions.
Author: Janne Rosberg <janne.rosberg@offcode.fi>
arch/arm/src/imxrt: Add imxrt_clockconfig.c/.h
configs/imxrt1050-evk: Add clock configuration definitions to board.h
arch/arm/src/imxrt: Fix CCM register name; Fix doubly defined in LPUART bit field.
arch/arm/src/imxrt: Add analog defines to CCM register definition header file.
Author: Gregory Nutt <gnutt@nuttx.org>
arch/arm/src/imxrt: Bring in GPIO C files from i.MX6. Things are in disarray now because that GPIO logic depends on IOMUXC logic which is not yet in place.
arch/arm/src/imxrt: Add a few more GPIO definitions to make the header file compatible with i.MX6
arch/arm/src/imxrt/chip: Add GPIO register definition file.
Author: Janne Rosberg <janne.rosberg@offcode.fi>
arch/arm/src/imxrt: Add DCDC register definitions.
arch/arm/srch/imxrt: Add CCM register bit definitions
Author: Gregory Nutt <gnutt@nuttx.org>
Purely cosmetic
arch/arm/src/imxrt: Add system reset controller register definition header file.
Embarassingly trivial change left in compiler.
arch/arm/src/imxrt: Finishes i.MX RT1050 LPUART register definition header file.
arch/arm/src/imxrt: Beginning of an i.MX RT1050 LPUART register definition header file.
Some trivial things
Author: Janne Rosberg <janne.rosberg@offcode.fi>
arch/arm/src/imxrt: Add imxrt_wdog.h
arch/arm/src/imxrt: Add initial imxrt_ccm.h
Author: Gregory Nutt <gnutt@nuttx.org>
Trivial update to README.
arch/arm/src/imxrt: The i.MX Rt implements 4 bits of interrupt priority, not two. Thanks, Janne.
arch/arm/src/imxrt: Fix some initial compile issues. Still a long way from complete, but there is a buildable environment now for the imxrt1050-evk.
configs/imxrt1050-evk: Add an initial NSH configuration for testing.
configs/Kconfig: Hook the i.MX RT 1050 board configuration into the NuttX configuration system.
configs/imxrt_evk: Add the framework for i.MX RT 1050 board support.
arch/arm/src/imxrt: Bring in a few more files from LPC54xxx.
arch/arm/src/imxrt: Bring in imxrt_clrpend() from the LPC54xxx.
arch/arm/src/imxrt: Bring in Cortex-M7 SysTick setup from the SAMv7.
arch/arm/src/imxrt: Add a few easy files.
arch/arm/src/imxrt/chip: Add memory map header files.
arch/arm/src/imxrt: A few basic files to start the port to the i.MX RT 1050.
Squashed commit of the following:
arch/arm/src/lpc54xx: Finish off some missing logic. Complete now execpt for GPIO and LED support.
arch/arm/src/lpc54xx: Add lpc54_clrpend.c
arch/arm/src/lpc54xx: Serial driver is complete and compiles.
arch/arm/src/lpc54xx: Add beginning of a serial driver (still missing some logic)
arch/arm/src/lpc54xx: Fleshes out low level USART intialization.
arch/arm/src/lpc546xx/Kconfig: Add hooks to integrate with common seril upper half.
arch/arm/src/lpc54xx: Beginning of USART console support.
arch/arm/src/lpc54xx: Completes very basic clock configuration.
arch/arm/src/lpc54xx: Add clocking logic (still not complete)
arch/arm/src/lpc54xx: Beginning of PLL configuration logic.
arch/arm/src/lpc54xx: Fix a few things from first compile attempt. Compilation cannot work until I at least finish the clock configuration logic.
arch/arm/src/lpc54xx: Addes some SysTick logic.
arch/arm/src/lpc54xx: Completes basic startup logic (sans clock configuration) and interrupt configuration.
arch/arm/src/lpc54xx: Add generic ARMv7-M start-up logic (needs LPC54628 customizations); add emtpy file that will eventually hold the clock configuration logic.
arch/arm/src/lpc54xx: Add (incomplete) SYSCON register definition header file.
arch/arm/src/lpc54xx: Add FLEXCOMM header file.
arch/arm/src/lpc54xx: Bring in tickless clock logic from LPC43; configs/lpcxpresso-lpc54628: mount procfs if enabled.
arch/arm/src/lpc54xx: Add RIT clock definitions; add SysTick initialization (not finished)
LPC54xx and LPCXpresso-LPC54628: add more boilerplate files and stubbed out files.
arch/arm/src/lpc54xx: Add (incomplete) USART header file.
Add another condition to a Kconfig; refresh a defconfig.
arch/arm/src/lpc54xx/chip: Add LPC54628 memory map header files.
configs/lpcxpresso-lpc54628: Add basic build files for the LPCXpresso-LPC54628
arch/: Basic build directory structure for the LPC54628
BCM2708: Add enough infrastructrue (more stubs) to get a clean compilation of the Pi Zero configuration (with many undefined things at link time).
BCM2708: Add basic interrupt handling logic
BCM2708: Add interrupt register definitions.
BCM2708: Add irq.h header file
BCM2708/Pi zero: bcm_boot.c and bcm_memorymap.h now compile. Added pizero linker script.
BCM2708/Pi Zero: Add Make.defs needed to build.
arch/arm/include/bcm2708, arch/arm/src/bcm2708, configs/pizero: Add some basic build and configuration logic.
configs/pizero: Add some basic structure of the Rasperry Pi Zero port.
Created directory configs/pizero. Nothing there now but a README.txt file.
Add initial boot.c and memorymap.c files
Author: Alan Carvalho de Assis <acassis@gmail.com>
Add AUX/UART/SPI registers definition
Author: Alan Carvalho de Assis <acassis@gmail.com>
Pizero GPIO registers
* Initial commit to add GPIO definitions
* Add remaining GPIO registers definition
Alan Carvalho de Assis <acassis@gmail.com>
BCM2708 memory map: Add VBASE defintions; fix VCSDRAM address per Alan; move all virtual address to the bottom of the file to avoid confusion -- top is all physical address; bottom is all veritural address.
Add initial memory map to BCM2708/BCM2835
Alan Carvalho de Assis <acassis@gmail.com>
- sam_gpioread: Now the actual line level from the pin is read back. This is extremely important for Open-Drain Pins, which can be used bidirectionally
- Re-Implemented twi_reset-function and enhanced it so it can be called from inside the driver (see next point)
- Glitch-Filter: Added a configuration option to enable the twi-built-in glitch filter
- Added a "Single Master Mode": In EMC Testing the TWI-Bus got stuck because the TWI-Master detected a Multi-Master access (but there is no second master). With the option "Single Master" we detect these events and automatically trigger a twi_reset. We also do an automatic recovery if a slave got stuck (SDA stays low).
With the above changes I²C-Bus reliability in harsh environments (eg. EMC) is greatly improved.
The small change in the GPIO-Driver was necessary because otherwise you cannot read back the correct line status of Open-Drain Outputs and this is needed by the twi_reset function.
