NuttX TODO List (Last updated April 12, 2009) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ (6) Task/Scheduler (sched/) (1) Dynamic loader (N/A) (2) Memory Managment (mm/) (1) Signals (sched/, arch/) (1) pthreads (sched/) (1) C++ Support (12) Network (net/, netutils/) (1) USB (drivers/usbdev) (4) Libraries (lib/) (6) File system/Generic drivers (fs/, drivers/) (2) Graphics subystem (graphics/) (1) Pascal add-on (pcode/) (0) Documentation (Documentation/) (5) Build system / Toolchains (2) NuttShell (NSH) (examples/nsh) (3) Other Applications & Tests (examples/) (1) Linux/Cywgin simulation (arch/sim) (2) ARM (arch/arm/) (1) ARM/C5471 (arch/arm/src/c5471/) (3) ARM/DM320 (arch/arm/src/dm320/) (2) ARM/i.MX (arch/arm/src/imx/) (3) ARM/LPC214x (arch/arm/src/lpc214x/) (4) ARM/STR71x (arch/arm/src/str71x/) (2) ARM/LM3S6918 (arch/arm/src/lm3s/) (4) pjrc-8052 / MCS51 (arch/pjrc-8051/) (2) Hitachi/Renesas SH-1 (arch/sh/src/sh1) (4) Renesas M16C/26 (arch/sh/src/m16c) (8) z80/z8/ez80 (arch/z80/) (8) z16 (arch/z16/) o Task/Scheduler (sched/) ^^^^^^^^^^^^^^^^^^^^^^^ Description: When a tasks exits, shouldn't all of its child pthreads also be terminated? Status: Open Priority: Medium, required for good emulation of process/pthread model. Description: atexit() supports registration of one function called on exit(). Should task_delete() also cause atexit() function to be called? Status: Open Priority: Low, task_delete() is non-standard and its behavior is unspecified. Description: Implement sys/mman.h and functions Status: Open Priority: Low Description: Implement sys/wait.h and functions. Consider implementing wait, waitpid, waitid. At present, a parent has no information about child tasks. Status: Open Priority: Low Description: Several APIs do not set errno. Need to review all APIs. Status: Open Priority: Medium, required for standard compliance (but makes the code bigger) Description: socket descriptors are not cloned as are file descriptors by task_create(). Status: Open Priority: Medium-to-High o Dynamic Loader ^^^^^^^^^^^^^^ Description: At some point in the future, I intend to port the XFLAT dynamic loader into NuttX (see http://xflat.sourceforge.net/). That would allow NuttX to dynamically load and link external code in a mounted filesystem. Status: Open Priority: Low, Nice feature and I might do it someday o Memory Managment (mm/) ^^^^^^^^^^^^^^^^^^^^^^ Description: Add an option to free all memory allocated by a task when the task exits. This is probably not be worth the overhead for a deeply embedded system. Status: Open Priority: Medium/Low, a good feature to prevent memory leaks but would have negative impact on memory usage and code size. Description: Current logic adapts size_t for 16-bit address machines vs. 32-bit address machines. But a small memory option should also be provided so that the small offset option can be used with 32-bit machines that have small RAM memories (like the lpc2148) Status: Open Priority: High, a good feature enhancement. o Signals (sched/, arch/) ^^^^^^^^^^^^^^^^^^^^^^^ Description: 'Standard' signals and signal actions are not supported. (e.g., SIGINT, SIGCHLD, SIGSEGV, etc). Status: Open Priority: Low, required by standards but not so critical for an embedded system. o pthreads (sched/) ^^^^^^^^^^^^^^^^^ Description: pthread_cancel(): Should implement cancellation points and pthread_testcancel() Status: Open Priority: Low, probably not that useful o C++ Support ^^^^^^^^^^^ Description: Need to call static constructors Status: Open Priority: Low, depends on toolchain. Call to gcc's built-in static constructor logic will probably have to be performed by user logic in user_start(). o Network (net/, netutils/) ^^^^^^^^^^^^^^^^^^^^^^^^^ Description: One critical part of netutils/ apps is untested: The uIP resolver in netutils/resolv. The webclient code has been tested on host using gethosbyname(), but still depends on the untested resolve logic. Status: Open Priority: Medium, Important but not core NuttX functionality Description: Should implement SOCK_RAW, SOCK_PACKET Status: Open Priority: Low Description: uIP polling issues / Multiple network interface support: (1) Current logic will not support multiple ethernet drivers. Each driver should poll on TCP connections connect on the network supported by the driver; UDP polling should respond with TX data only if the UDP packet is intended for the the network supported by the driver. (2) If there were multiple drivers, polling would occur at double the rate. Fix by using bound IP address in TCP connection (lipaddr) and verifying that it is in the subnet served by the driver. Status: Open Priority: Medium, The feature is not important, but it is important for NuttX to resolve the architectural issues. Description: Sendoto() and multiple network interface support: When polled, would have to assure that the destination IP is on the subnet served by the polling driver. Status: Open Priority: Medium, The feature is not important, but it is important for NuttX to resolve the architectural issues. Description: IPv6 support is incomplete. Adam Dunkels has recently announced IPv6 support for uIP (currently only as part of Contiki). Those changes need to be ported to NuttX. Status: Open Priority: Medium Description: Incoming UDP broadcast should only be accepted if listening on INADDR_ANY(?) Status: Open Priority: Low Description: Read-ahead buffers capture incoming TCP data when no user thread is recv-ing the data. Should add some driver call to support throttling; when there is no listener for new data, the driver should be throttled. Perhaps the driver should disable RX interrupts when throttled and re-anable on each poll time. recvfrom would, of course, have to un-throttle. Status: Open Priority: Medium Description: Need to standardize collection of statistics from network drivers. examples/nsh ifconfig command should present statistics. Status: Open Priority: Low Description: Outgoing packets are dropped and overwritten by ARP packets if the destination IP has not been mapped to a MAC. Could improve send() performance by explicitly performing ARP before sending the packet. Status: Open Priority: Medium Description: Port PPP support from http://contiki.cvs.sourceforge.net/contiki/contiki-2.x/backyard/core/net/ppp/ Status: Open Priority: Low Description: At present, there cannot be two concurrent active TCP send operations in progress using the same socket. This is because the uIP ACK logic will support only one transfer at a time. The solution is simple: A mutex will be needed to make sure that each send that is started is able to be the exclusive sender until all of the data to be sent has been ACKed. Status: Open. There is some temporary logic to examples/nsh that does this same fix and that temporary logic should be removed when send() is fixed. Priority: Medium-Low. This is an important issue for applications that send on the same TCP socket from multiple threads. Description: TCP supports read-ahead buffering to handle the receipt of TCP/IP packets when there is no read() in place. Should such capability be useful for UDP? PRO: Would reduce packet loss and enable support for poll()/select(). CON: UDP is inherently lossy so why waste memory footprint? Status: Open Priority: Medium Description: poll()/select() is not implemented for UDP sockets because they do do not support read-ahead buffering. Therefore, there is never a case where you can read from a UDP socket without blocking. Status: Open, depends on UDP read-ahead support Priority: Medium o USB (drivers/usbdev) ^^^^^^^^^^^^^^^^^^^^ Description: The USB bulk storage class driver configuration (examples/usbstorage) does not work reliably when debug is disabled (CONFIG_DEBUG+CONFIG_DEBUG_VERBOSE +CONFIG_DEBUG_USB) on WinXP (Linux appears to be fine). A race condition would would be a possibility. The symptom is that that WinXP sends a MODE SENSE (6) command with an unsupported mode page (0x1c/0x00) Status: Open Priority: High o Libraries (lib/) ^^^^^^^^^^^^^^^^ Description: sscanf() and lib_vsprintf() do not support floating point values. Status: Open Priority: Low Description: The definition of environ in stdlib.h is bogus and will not work as it should. This is because the underlying representation of the environment is not an arry of pointers. Status: Open Priority: Medium Description: fgets implementation does not use C-buffered I/O, but rather talks to serial driver directly via read(). It includes VT-100 specific editting commands. This gets should be renamed readlin() and a more generic fgets() should be implemented. Status: Open Priority: Low (unless you are using mixed C-buffered I/O with fgets and fgetc, for example). Description: Need some minimal termios support... at a minimum, enough to switch between raw and "normal" modes to support behavior like that needed for readline(). Status: Open Priority: Low o File system / Generic drivers (fs/, drivers/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: Implement chmod(), truncate(). Status: Open Priority: Low Description: FAT: long file names Status: Open Priority: Medium Description: The CAN driver is untested. Add a test for the CAN driver. Status: Open Priority: Medium Description: At present, the CAN driver does not support the poll() method. Status: Open Priority: Low Description: There is no way to remove a FIFO or PIPE created in the psuedo filesystem. Once created, they persist indefinitely and cannot be unlinked. This is actually a more generic issue: unlink does not work for anything in the psuedo- filesystem. Status: Open, but partially resolved: pipe buffer is at least freed when there are not open references to the pipe/FIFO. Priority: Medium Description: The ROMFS file system does not verify checksums on either volume header on on the individual files. Status: Open Priority: Low. I have mixed feelings about if NuttX should pay a performance penalty for better data integrity. Description: FAT: FAT32 is untested -- because I don't have any large enough devices yet to support a FAT32 FS. Status: Open Priority: Medium Description: The simple SPI based MMCS/SD driver in fs/mmcsd does not yet handle multiple block transfers. Status: Open Priority: Medium-Low o Graphics subystem (graphics/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: If CONFIG_NX is enabled, the build fails the first time saying that there is "No rule to make target..." for one of the auto-generated graphics files. This is a nuisance, but if you simply build again (with the source files already auto-generated) the problem does not reoccur. Status: Open Priority: Low, the work-around is simple Description: Testing of all APIs is not complete. See http://nuttx.sourceforge.net/NXGraphicsSubsystem.html#testcoverage Status: Open Priority: Medium o Pascal Add-On (pcode/) ^^^^^^^^^^^^^^^^^^^^^^ Description: Need APIs to verify execution of P-Code from memory buffer. Status: Open Priority: Low Description: Loader and object format may be too large for some small memory systems. Consider ways to reduce memory footprint. Status: Open Priority: Medium o Documentation (Documentation/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ o Build system ^^^^^^^^^^^^ Description: Some names under arch are still incorrect. These should be processor architecture names: pjrc-8051 should be 805x Status: Open Priority: Low Description: configs/pjrc-8051 should be configs/pjrc-87c52 Status: Open Priority: Low Description: Dependencies do not work correctly under configs//src (same as arch//src/board). Status: Open Priority: Medium (maybe higher for z80 target) Description: It would be nice to de-couple some of the behaviors enabled by CONFIG_DEBUG. For example, CONFIG_DEBUG turns on debug output, but also disables optimization make the binary much bigger. Status: Open Priority: Low. There workaround is easy.. just edit the configuration's Make.def file to control the behavior that you want. Description: Need a NuttX configuration tool. The number of configuration settings has become quite large and difficult to manage manually. Status: Open Priority: Medium-low o NuttShell (NSH) (examples/nsh) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: When the telnetd front end is received, each TCP packet received causes a prompt (nsh >) to be presented. The prompt should only be presented when the user enters a carriage return. Status: Open Priority: Low Description: The wget command has been incorporated into NSH, however it is still untested as of this writing (only because I have not had the correct network setup for the testing yet). Since wget depends on the also untest uIP resolv/ logic, it is like non-functional. Status: Open Priority: Med-High o Other Applications & Tests (examples/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: The redirection test (part of examples/pipe) terminates incorrectly on the Cywgin-based simulation platform (but works fine on the Linux-based simulation platform). Status: Open Priority: Low Description: examples/wget is untested on the target (it has been tested on the host, but not in the target using the uIP resolv logic). Status: Open Priority: Med Description: examples/sendmail is untested on the target (it has been tested on the host, but not on the target. Status: Open Priority: Med o Linux/Cywgin simulation (arch/sim) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: The simulated serial driver has some odd behavior. It will stall for a long time on reads when the C stdio buffers are being refilled. This only effects the behavior of things like fgetc(). Workaround: Set CONFIG_STDIO_BUFFER_SIZE=0, suppressing all C buffered I/O. Status: Open Priority: Low (because the simulator is only a test/development platform) o ARM (arch/arm/) ^^^^^^^^^^^^^^^ Description: ARM interrupt handling performance could be improved in many ways. One easy way is to use a pointer to the context save area in current_regs instead of using up_copystate so much. see handling of 'current_regs" in arch/sh/src/common/* for examples of how this might be done. Status: Open Priority: Low Description: The ARM interrupt handler restores all regisers upon return. This could be improved as well: If there is not context switch, then the static registers need not be restored because they will not be modified by the called C code. (see arch/sh/src/sh1/sh1_vector.S for example) Status: Open Priority: Low o ARM/C5471 (arch/arm/src/c5471/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: UART re-configuration is untested and conditionally compiled out. Status: Open Priority: Medium. ttyS1 is not configured, but not used; ttyS0 is configured by the bootloader o ARM/DM320 (arch/arm/src/dm320/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: config/ntos-dm320: It seems that when a lot of debug statements are added, the system no longer boots. This is suspected to be a stack problem: Making the stack bigger or removing arrays on the stack seems to fix the problem (might also be the bootloader overwriting memory) Status: Open Priority: Medium Description: A USB device controller driver was added but has never been tested. Status: Open Priority: Medium Description: A framebuffer "driver" was added, however, it remains untested. Status: Open Priority: Medium Description: In order to use the framebuffer "driver" additional video encoder logic is required to setupt composite video output or to interface with an LCD. Status: Open Priority: Medium (high if you need to use the framebuffer driver) o ARM/i.MX (arch/arm/src/imx/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: The basic port of the i.MX1 architecuture is underway. The port is incomplete (as of this writing, is still lacks a timer, interrupt decoding, USB, network) and untested. Status: Open (and in work) Priority: Medium (high if you need i.MX1/L support) Description: SPI methods are not thread safe. Needs a semaphore to protect from re-entrancy. Status: Open Priority: Medium -- Will be very high if you do SPI access from multiple threads. o ARM/LPC214x (arch/arm/src/lpc214x/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: Should use Vector Interrupts Status: Open Priority: Low Description: USB DMA not fully implemented. Partial logic is in place but it is fragmentary and bogus. Status: Open Priority: Low Description: USB Serial Driver reports wrong error when opened before the USB is connected (reports EBADF instead of ENOTCONN) Status: Open Priority: Low Description: The USB bulk storage class driver configuration (examples/usbstorage) does not work reliably when debug is disabled (CONFIG_DEBUG+CONFIG_DEBUG_VERBOSE +CONFIG_DEBUG_USB) on WinXP (Linux appears to be fine). A race condition would would be a possibility. The symptom is that that WinXP sends a MODE SENSE (6) command with an unsupported mode page (0x1c/0x00) Status: Open Priority: High Description: At present the SPI driver is polled. Should it be interrupt driven? Look at arch/arm/src/imx/imx_spi.c -- that is a good example of an interrupt driven SPI driver. Should be very easy to part that architecture to the LPC. Status: Open Priority: Medium Description: SPI methods are not thread safe. Needs a semaphore to protect from re-entrancy. Status: Open Priority: Medium -- Will be very high if you do SPI access from multiple threads. Description: At present the SPI driver is polled -AND- there is a rather large, arbitrary, delay in one of the block access routines. The purpose of the delay is to avoid a race conditions. This begs for a re-design -OR- at a minimum, some optimiation of the delay time. Status: Open Priority: Medium o ARM/STR71x (arch/arm/src/str71x/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: Basic port is complete but untested. Complete integration Status: Open Priority: High Description: Add SPI driver and integrate with MMC/SD support. Status: Open Priority: Medium Description: Develop a USB driver and integrate with existing USB serial and storage class drivers. Status: Open Priority: Medium Description: SPI methods are not thread safe. Needs a semaphore to protect from re-entrancy. Status: Open Priority: Medium -- Will be very high if you do SPI access from multiple threads. o ARM/LM3S6918 (arch/arm/src/lm3s/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: Eagle-100 LEDs do not work. This has to be a simple problem to fix. Status: Open Priority: Low Description: Still need to implement I2C Status: Open Priority: Low o pjrc-8052 / MCS51 (arch/pjrc-8051/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: Current status: - Basic OS task management seems OK - Fails when interrupts enabled. The stack pointer is around 0x6e before the failure occurs. It looks like some issue when the stack pointer moves from the directly to indirectly addressable region (0x80 boundary). - Work on the 8052 is temporarily on hold Status: Open Priority: Low, 8051 is a tough platform because of the tiny stack. Description: Use timer 0 as system timer. Timer 2 is needed for second UART. Logic is implemented, but there needs to be a system configuration to change the ticks-per-second value to match the timer interrupt rate Status: Open Priority: Low Description: During build, there are several integer overflows reported: sched/gmtime_r.c aroud lines 184 and 185 sched/clock_initialize.c at line 107 sched/pthread_create.c at 330 examples/ostest/barrier.c around lines 53 and 74 examples/ostest/sighand.c at 225 and 244 driver/serial.c in usleep calls around 347 and 354 Status: Open Priority: Medium Description Global data is not being initialized. Logic like that of SDCCs crt0*.s needs to be incorporated into the system boot logic Status: Open Priority: Low -- only because there as so many other issues with 8051 o Hitachi/Renesas SH-1 (arch/sh/src/sh1) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: There are instabilities that make the SH-1 port un-usable. The nature of these is not understood; the behavior is that certain SH-1 instructions stop working as advertised. I have seen the following examples: 412b jmp @r1 - Set a return address in PR, i.e., it behaved like 410b jsr @r1. Normally 412b works correctly, but in the failure condition, it reliably set the PR. 69F6 mov.l @r15+,r9 - wrote the value of R1 to @r15+. This behavior does not correspond to any known SH-1 instruction This could be a silicon problem, some pipeline issue that is not handled properly by the gcc 3.4.5 toolchain (which has very limit SH-1 support to begin with), or perhaps with the CMON debugger. At any rate, I have exhausted all of the energy that I am willing to put into this cool old processor for the time being. Status: Open Priority: Low -- because the SH-1, SH7032, is very old and only of historical interest. Description: arch/sh has been restructured to support M16C. Need to verify that SH-1 still builds. Status: Open Priority: Low Description: The M16C target cannot be built. The GNU m16c-elf-ld link fails with the following message: m32c-elf-ld: BFD (GNU Binutils) 2.19 assertion fail /home/Owner/projects/nuttx/buildroot/toolchain_build_m32c/binutils-2.19/bfd/elf32-m32c.c:482 Where the reference line is: /* If the symbol is out of range for a 16-bit address, we must have allocated a plt entry. */ BFD_ASSERT (*plt_offset != (bfd_vma) -1); No workaround is known at this time. Status: Open Priority: High -- this is a show stopper for M16C. o Renesas M16C/26 (arch/sh/src/m16c) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: Coding of the initial port is complete, but is untested. Status: Open Priority: Low Description: Serial drivers were developed for the M16C, however, the SKP16C26 StarterKit has no serial connectors. Status: Open Priority: Low Description: Should implement SPI, I2C, Virual EEPROM, FLASH, RTC drivers Status: Open Priority: Medium o z80/z8/ez80 (arch/z80) ^^^^^^^^^^^^^^^^^^^^^^^ Description: The SDCC version the same problems with interger overflow during compilation as described for pjrc-8051. At typical cause is code like usleep(500*1000) which exceeds the range of a 16-bit integer Status: See pjrc-8051 Priority: See pjrc-8051 Description: The simulated Z80 serial console (configs/z80sim/src/z80_serial.c + driver/serial.c) does not work. This is because there are no interrupts in the simulation so there is never any serial traffic. Status: Open Priority: Low -- the simulated console is not critical path and the designs to solve the problem are complex. Description: ZDS-II Librarian complains that the source for the .obj file is not in the library. Status: Open Priority: Low, thought to be cosmetic. I think this is a consequence of replacing vs. inserting the library. Description: The ZDS-II compiler (version 4.10.1) fails with an internal error while compiler mm/mm_initialize. This has been reported as incident 81509. I have found the following workaround that I use to build for the time being: --- mm/mm_initialize.c.SAVE 2008-02-13 08:06:46.833857700 -0600 +++ mm/mm_initialize.c 2008-02-13 08:07:26.367608900 -0600 @@ -94,8 +94,11 @@ { int i; +#if 0 /* DO NOT CHECK IN */ CHECK_ALLOCNODE_SIZE; CHECK_FREENODE_SIZE; +#endif /* Set up global variables */ Status: Open Priority: High Description: Add support for prioritized ez8 interrupts. Currently logic supports only nominal interrupt priority. Status: Open Priority: Low Description: The z8Encore! port has only been verified on the ZDS-II instruction set simulator. Status: Open Priority: Medium Description: Upgrade to the ZDS-II Z8Encore! 4.11.0 toolchain Status: Open Priority: Low Description: The XTRS target (configs/xtrs) has a clean problem. The clean rule removes .asm files. This works because there are no .asm files except in sub-directories that are provided from 'make clean' -- except for XTRS: It has a .asm file in its src/ directory that gets removed everytime clean is performd. Status: Open Priority: High if you happen to be working with XTRS. Description: A "generic" SPI and I2C drivers have been coded for the eZ80Acclaim! However, these remains untested since I have no SPI or I2C devices for the board (yet). Status: Open Priority: Med Description: SPI methods are not thread safe. Needs a semaphore to protect from re-entrancy. Status: Open Priority: Medium -- Will be very high if you do SPI access from multiple threads. Description: A "generic" I2C driver has been coded for the eZ8Encore! However, this remains untested since I have no I2C devices for the board (yet). Status: Open Priority: Med o z16 (arch/z16) ^^^^^^^^^^^^^^^^ Description: ZDS-II Librarian complains that the source for the .obj file is not in the library. Status: Open Priority: Low, thought to be cosmetic. I think this is a consequence of replacing vs. inserting the library. Description: When the interrupt-driven serial driver is used, the system hangs. This is because of TX ready (TRDE) interrupts that get lost while interrupts are disabled. The existing serial driver appears to be limited to hardware with a latching, level-sensitive TX ready interrupt. Status: Open Priority: Medium. A polled, write-only serial driver is used in the interim for system testing. Description: The system delays do not appear to be correct with the examples/ostest/timedmqueue.c test. Status: Open Priority: Medium-High Description: At present, the z16f port does not run properly when CONFIG_DEBUG is disabled: The obvious symptom is that there is no printf() output. I have isolated with problem to errors in optimization. With -reduceopt on the command line, I can get the printf output. However, there are still errors in the compiled code -- specifically in sched/timer_create.c. I have submitted a bug report to ZiLOG for this (support incident 81400). You can see the status of the bug report (and lots more technical detail) here: http://support.zilog.com/support/incident/incident_support.asp?iIncidentId=81400&iSiteId=1&chLanguageCode=ENG Summary of ZiLOG analysis: "This is a ZNEO compiler problem. ... [a] workaround is to replace: if ( !timerid || (clockid != 0) ) By: if ((clockid != 0) || !timerid)" Status: Open Priority: Medium-High Description: The pascal add-on does not work with the z16f (that is configuration z16f2800100zcog/pashello). This appears to be another ZDS-II error: when executing the instruction SYSIO 0, WRITESTR a large case statement is executed. This involves a call into the ZiLOG runtime library to __uwcase(). __uwcase is passed a pointer to a structure containing jump information. The cause of the failure appears to be that the referenced switch data is bad. This is submited as ZiLOG support incident 81459. Summary of ZiLOG analysis: "This is a ZNEO run time library problem. One workaround is to replace the line 58 in uwcase.asm From: ADD R9,#4 ; Skip handler To: ADD R9,#2 ; Skip handler And add uwcase.asm to the project. If the customer does not want to modify uwcase.asm then the other workaround is to add a dummy case and make it same as default: case 0x8000: default: This will make sure that uwcase is not called but ulcase is called." Status: Open. Due to licensing issues, I cannot include the modified uwcase in the NuttX code base. Priority: Medium Description: Add support to maintain SPOV in context switching. This improvement will provide protection against stack overflow and make a safer system solution. Status: Open Priority: Low Description: Add support for prioritized interrupts. Currently logic supports only nominal interrupt priority. Status: Open Priority: Low Description: Upgrade to the ZDS-II ZNEO 4.11.1 toolchain Status: Open Priority: Low