# vTaskDelayUntil not working with mega128 **URL:** \ **Category:** Kernel\ **Created:** [March 15, 2007, 2:05pm UTC](https://forums.freertos.org/t/vtaskdelayuntil-not-working-with-mega128/2977 "2007-03-15T14:05:08Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\ **Post date:** [March 15, 2007, 2:05pm UTC](https://forums.freertos.org/t/vtaskdelayuntil-not-working-with-mega128/2977/1 "2007-03-15T14:05:08Z")
**nobody** wrote on [Thursday, March 15, 2007](https://sourceforge.net/p/freertos/discussion/382005/thread/83de552e/#f123): hi I implemented a simple code, with a single task . The program control is lost when it reaches vTaskDelayUntil. If simple delay (using for loop) is used the program works fine . I have changed from mega323 to mega128 in make file settings in FreeRtosConfig.h are #define configUSE\_PREEMPTION        1 #define configUSE\_IDLE\_HOOK            0 #define configUSE\_TICK\_HOOK            0 #define configCPU\_CLOCK\_HZ            ( ( unsigned portLONG ) 8000000 ) #define configTICK\_RATE\_HZ            ( ( portTickType ) 1000 ) #define configMAX\_PRIORITIES        ( ( unsigned portBASE\_TYPE ) 4 ) #define configMINIMAL\_STACK\_SIZE    ( ( unsigned portSHORT ) 85 ) #define configTOTAL\_HEAP\_SIZE        ( (size\_t ) ( 2500 ) ) #define configMAX\_TASK\_NAME\_LEN        ( 8 ) #define configUSE\_TRACE\_FACILITY    0 #define configUSE\_16\_BIT\_TICKS        1 #define configIDLE\_SHOULD\_YIELD        1 ---
**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\ **Post date:** [April 12, 2007, 6:54am UTC](https://forums.freertos.org/t/vtaskdelayuntil-not-working-with-mega128/2977/2 "2007-04-12T06:54:37Z")
**nobody** wrote on [Thursday, April 12, 2007](https://sourceforge.net/p/freertos/discussion/382005/thread/83de552e/#f123/c544): I also have the same problem with an ATMEGA162!!! It works fine on my ATMEGA16, I use vTaskDelay and also vTaskDelayUntil, but when I try this on ATMEGA162, it never comes again, after the call to this functions! If anyone has identified the problem, please let us know! ---
**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\ **Post date:** [April 12, 2007, 8:40am UTC](https://forums.freertos.org/t/vtaskdelayuntil-not-working-with-mega128/2977/3 "2007-04-12T08:40:39Z")
**[embeddedc](https://sourceforge.net/u/embeddedc/)** wrote on [Thursday, April 12, 2007](https://sourceforge.net/p/freertos/discussion/382005/thread/83de552e/#f123/c544/1744): I’m not too familiar with the AVR, but having had a quick look at the two devices (16 and 162) there seems to be little difference.  The 162 does have more timers through.  Is it possible that the timer setup used on the 16 is not compatible with the 162 and the tick is not running?  If you have a good debugger then try setting a break point in the tick interrupt.  If you cannot do this then try writing a tick hook function that toggles and LED every 1000 ticks.  If this does not work then maybe the timer interrupt is not running and this is the source of your problem? ---
**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\ **Post date:** [April 13, 2007, 4:38am UTC](https://forums.freertos.org/t/vtaskdelayuntil-not-working-with-mega128/2977/4 "2007-04-13T04:38:58Z")
**nobody** wrote on [Friday, April 13, 2007](https://sourceforge.net/p/freertos/discussion/382005/thread/83de552e/#f123/965e): Hi, thanks for your respond. You´re right, I thought I had configured the timer, but there are some changes in the TIMSK register between the ATMEGA16 and the ATMEGA162 I didnt noticed! The other timer registers seem to be the same. Well, it works now for me. Here´s the code, modified for use of timer2 instead of timer1 (I need two counters for my application, and timer3 is already busy!), it´s working good. /\*     [FreeRTOS.org](http://FreeRTOS.org) V4.1.3 - Copyright (C) 2003-2006 Richard Barry.     This file is part of the [FreeRTOS.org](http://FreeRTOS.org) distribution.     [FreeRTOS.org](http://FreeRTOS.org) is free software; you can redistribute it and/or modify     it under the terms of the GNU General Public License as published by     the Free Software Foundation; either version 2 of the License, or     (at your option) any later version.     [FreeRTOS.org](http://FreeRTOS.org) is distributed in the hope that it will be useful,     but WITHOUT ANY WARRANTY; without even the implied warranty of     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the     GNU General Public License for more details.     You should have received a copy of the GNU General Public License     along with [FreeRTOS.org](http://FreeRTOS.org); if not, write to the Free Software     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA     A special exception to the GPL can be applied should you wish to distribute     a combined work that includes [FreeRTOS.org](http://FreeRTOS.org), without being obliged to provide     the source code for any proprietary components.  See the licensing section     of [http://www.FreeRTOS.org](http://www.FreeRTOS.org) for full details of how and when the exception     can be applied.     \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*     See [http://www.FreeRTOS.org](http://www.FreeRTOS.org) for documentation, latest information, license     and contact details.  Please ensure to read the configuration and relevant     port sections of the online documentation.     \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* \*/ /\* Changes from V2.6.0     + AVR port - Replaced the inb() and outb() functions with direct memory       access.  This allows the port to be built with the 20050414 build of       WinAVR. \*/ /\* PUSTOWKA Changes     this port is using timer2 instead of timer1, and it is modified,  for     the use with ATMEGA162. see below for further indications! \*/ #include \ #include \ #include "FreeRTOS.h" #include "task.h" /\*----------------------------------------------------------- \* Implementation of functions defined in portable.h for the AVR port. \*----------------------------------------------------------\*/ /\* Start tasks with interrupts enables. \*/ #define portFLAGS\_INT\_ENABLED                    ( ( portSTACK\_TYPE ) 0x80 ) /\* Hardware constants for timer 1. \*/ #define portCLEAR\_COUNTER\_ON\_MATCH                ( ( unsigned portCHAR ) 0x08 ) #define portPRESCALE\_64                            ( ( unsigned portCHAR ) 0x04 ) #define portCLOCK\_PRESCALER                        ( ( unsigned portLONG ) 64 ) #define portCOMPARE\_MATCH\_A\_INTERRUPT\_ENABLE    ( ( unsigned portCHAR ) 0x10 ) /\*-----------------------------------------------------------\*/ /\* We require the address of the pxCurrentTCB variable, but don’t want to know any details of its type. \*/ typedef void tskTCB; extern volatile tskTCB \* volatile pxCurrentTCB; /\*-----------------------------------------------------------\*/ /\* \* Macro to save all the general purpose registers, the save the stack pointer \* into the TCB.  \* \* The first thing we do is save the flags then disable interrupts.  This is to \* guard our stack against having a context switch interrupt after we have already \* pushed the registers onto the stack - causing the 32 registers to be on the \* stack twice. \* \* r1 is set to zero as the compiler expects it to be thus, however some \* of the math routines make use of R1. \* \* The interrupts will have been disabled during the call to portSAVE\_CONTEXT() \* so we need not worry about reading/writing to the stack pointer. \*/ #define portSAVE\_CONTEXT()                                        asm volatile (    "push    r0                        \n\t"                        "in        r0, \_\_SREG\_\_            \n\t"                        "cli                            \n\t"                        "push    r0                        \n\t"                        "push    r1                        \n\t"                        "clr    r1                        \n\t"                        "push    r2                        \n\t"                        "push    r3                        \n\t"                        "push    r4                        \n\t"                        "push    r5                        \n\t"                        "push    r6                        \n\t"                        "push    r7                        \n\t"                        "push    r8                        \n\t"                        "push    r9                        \n\t"                        "push    r10                        \n\t"                        "push    r11                        \n\t"                        "push    r12                        \n\t"                        "push    r13                        \n\t"                        "push    r14                        \n\t"                        "push    r15                        \n\t"                        "push    r16                        \n\t"                        "push    r17                        \n\t"                        "push    r18                        \n\t"                        "push    r19                        \n\t"                        "push    r20                        \n\t"                        "push    r21                        \n\t"                        "push    r22                        \n\t"                        "push    r23                        \n\t"                        "push    r24                        \n\t"                        "push    r25                        \n\t"                        "push    r26                        \n\t"                        "push    r27                        \n\t"                        "push    r28                        \n\t"                        "push    r29                        \n\t"                        "push    r30                        \n\t"                        "push    r31                        \n\t"                        "lds    r26, pxCurrentTCB        \n\t"                        "lds    r27, pxCurrentTCB + 1    \n\t"                        "in        r0, 0x3d                \n\t"                        "st        x+, r0                    \n\t"                        "in        r0, 0x3e                \n\t"                        "st        x+, r0                    \n\t"                    ); /\* \* Opposite to portSAVE\_CONTEXT().  Interrupts will have been disabled during \* the context save so we can write to the stack pointer. \*/ #define portRESTORE\_CONTEXT()                                    asm volatile (    "lds    r26, pxCurrentTCB        \n\t"                        "lds    r27, pxCurrentTCB + 1    \n\t"                        "ld        r28, x+                    \n\t"                        "out    \_\_SP\_L\_\_, r28            \n\t"                        "ld        r29, x+                    \n\t"                        "out    \_\_SP\_H\_\_, r29            \n\t"                        "pop    r31                        \n\t"                        "pop    r30                        \n\t"                        "pop    r29                        \n\t"                        "pop    r28                        \n\t"                        "pop    r27                        \n\t"                        "pop    r26                        \n\t"                        "pop    r25                        \n\t"                        "pop    r24                        \n\t"                        "pop    r23                        \n\t"                        "pop    r22                        \n\t"                        "pop    r21                        \n\t"                        "pop    r20                        \n\t"                        "pop    r19                        \n\t"                        "pop    r18                        \n\t"                        "pop    r17                        \n\t"                        "pop    r16                        \n\t"                        "pop    r15                        \n\t"                        "pop    r14                        \n\t"                        "pop    r13                        \n\t"                        "pop    r12                        \n\t"                        "pop    r11                        \n\t"                        "pop    r10                        \n\t"                        "pop    r9                        \n\t"                        "pop    r8                        \n\t"                        "pop    r7                        \n\t"                        "pop    r6                        \n\t"                        "pop    r5                        \n\t"                        "pop    r4                        \n\t"                        "pop    r3                        \n\t"                        "pop    r2                        \n\t"                        "pop    r1                        \n\t"                        "pop    r0                        \n\t"                        "out    \_\_SREG\_\_, r0            \n\t"                        "pop    r0                        \n\t"                    ); /\*-----------------------------------------------------------\*/ /\* \* Perform hardware setup to enable ticks from timer 1, compare match A. \*/ static void prvSetupTimerInterrupt( void ); /\*-----------------------------------------------------------\*/ /\* \* See header file for description. \*/ portSTACK\_TYPE \*pxPortInitialiseStack( portSTACK\_TYPE \*pxTopOfStack, pdTASK\_CODE pxCode, void \*pvParameters ) { unsigned portSHORT usAddress;     /\* Place a few bytes of known values on the bottom of the stack.     This is just useful for debugging. \*/     \*pxTopOfStack = 0x11;     pxTopOfStack–;     \*pxTopOfStack = 0x22;     pxTopOfStack–;     \*pxTopOfStack = 0x33;     pxTopOfStack–;     /\* Simulate how the stack would look after a call to vPortYield() generated by     the compiler. \*/     /\*lint -e950 -e611 -e923 Lint doesn’t like this much - but nothing I can do about it. \*/     /\* The start of the task code will be popped off the stack last, so place     it on first. \*/     usAddress = ( unsigned portSHORT ) pxCode;     \*pxTopOfStack = ( portSTACK\_TYPE ) ( usAddress & ( unsigned portSHORT ) 0x00ff );     pxTopOfStack–;     usAddress \>\>= 8;     \*pxTopOfStack = ( portSTACK\_TYPE ) ( usAddress & ( unsigned portSHORT ) 0x00ff );     pxTopOfStack–;     /\* Next simulate the stack as if after a call to portSAVE\_CONTEXT().      portSAVE\_CONTEXT places the flags on the stack immediately after r0     to ensure the interrupts get disabled as soon as possible, and so ensuring     the stack use is minimal should a context switch interrupt occur. \*/     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x00;    /\* R0 \*/     pxTopOfStack–;     \*pxTopOfStack = portFLAGS\_INT\_ENABLED;     pxTopOfStack–;     /\* Now the remaining registers.   The compiler expects R1 to be 0. \*/     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x00;    /\* R1 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x02;    /\* R2 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x03;    /\* R3 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x04;    /\* R4 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x05;    /\* R5 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x06;    /\* R6 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x07;    /\* R7 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x08;    /\* R8 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x09;    /\* R9 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x10;    /\* R10 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x11;    /\* R11 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x12;    /\* R12 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x13;    /\* R13 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x14;    /\* R14 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x15;    /\* R15 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x16;    /\* R16 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x17;    /\* R17 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x18;    /\* R18 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x19;    /\* R19 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x20;    /\* R20 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x21;    /\* R21 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x22;    /\* R22 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x23;    /\* R23 \*/     pxTopOfStack–;     /\* Place the parameter on the stack in the expected location. \*/     usAddress = ( unsigned portSHORT ) pvParameters;     \*pxTopOfStack = ( portSTACK\_TYPE ) ( usAddress & ( unsigned portSHORT ) 0x00ff );     pxTopOfStack–;     usAddress \>\>= 8;     \*pxTopOfStack = ( portSTACK\_TYPE ) ( usAddress & ( unsigned portSHORT ) 0x00ff );     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x26;    /\* R26 X \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x27;    /\* R27 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x28;    /\* R28 Y \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x29;    /\* R29 \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x30;    /\* R30 Z \*/     pxTopOfStack–;     \*pxTopOfStack = ( portSTACK\_TYPE ) 0x031;    /\* R31 \*/     pxTopOfStack–;     /\*lint +e950 +e611 +e923 \*/     return pxTopOfStack; } /\*-----------------------------------------------------------\*/ portBASE\_TYPE xPortStartScheduler( void ) {     /\* In this port we ignore the parameter and use the configUSE\_PREEMPTION     definition instead. \*/     /\* Setup the hardware to generate the tick. \*/     prvSetupTimerInterrupt();     /\* Restore the context of the first task that is going to run. \*/     portRESTORE\_CONTEXT();     /\* Simulate a function call end as generated by the compiler.  We will now     jump to the start of the task the context of which we have just restored. \*/     asm volatile ( "ret" );     /\* Should not get here. \*/     return pdTRUE; } /\*-----------------------------------------------------------\*/ void vPortEndScheduler( void ) {     /\* It is unlikely that the AVR port will get stopped.  If required simply     disable the tick interrupt here. \*/ } /\*-----------------------------------------------------------\*/ /\* \* Manual context switch.  The first thing we do is save the registers so we \* can use a naked attribute. \*/ void vPortYield( void ) \_\_attribute\_\_ ( ( naked ) ); void vPortYield( void ) {     portSAVE\_CONTEXT();     vTaskSwitchContext();     portRESTORE\_CONTEXT();     asm volatile ( "ret" ); } /\*-----------------------------------------------------------\*/ /\* \* Context switch function used by the tick.  This must be identical to \* vPortYield() from the call to vTaskSwitchContext() onwards.  The only \* difference from vPortYield() is the tick count is incremented as the \* call comes from the tick ISR. \*/ void vPortYieldFromTick( void ) \_\_attribute\_\_ ( ( naked ) ); void vPortYieldFromTick( void ) {     portSAVE\_CONTEXT();     vTaskIncrementTick();     vTaskSwitchContext();     portRESTORE\_CONTEXT();     asm volatile ( "ret" ); } /\*-----------------------------------------------------------\*/ /\* \* Setup timer 1 compare match A to generate a tick interrupt. \*/ static void prvSetupTimerInterrupt( void ) { unsigned portLONG ulCompareMatch; unsigned portCHAR ucLowByte;     /\*This is a personal modification. The timer normally used is Timer 1, having 16 bits.      Timer1 is used for counting of external events on my app.      One of the consequences of changing the timer to one of 8 bits, is that the configTICK\_RATE\_HZ      cannot be too small compared to the configCPU\_CLOCK\_HZ. The relation between them follows the      ecuation:           configTICK\_RATE\_HZ \>= configCPU\_CLOCK\_HZ / 16384          \*/         /\* Using 8bit timer 2 to generate the tick.  Correct fuses must be     selected for the configCPU\_CLOCK\_HZ clock. \*/     ulCompareMatch = configCPU\_CLOCK\_HZ / configTICK\_RATE\_HZ;     /\* We only have 8 bits so have to scale to get our required tick rate. \*/     ulCompareMatch /= portCLOCK\_PRESCALER; //    value/64     /\* Adjust for correct value. \*/     ulCompareMatch -= ( unsigned portLONG ) 1;     /\* Setup compare match value for compare match A.  Interrupts are disabled     before this is called so we need not worry here. \*/     ucLowByte = ( unsigned portCHAR ) ( ulCompareMatch & ( unsigned portLONG ) 0xff );     OCR2 = ucLowByte;     /\* Setup clock source and compare match behaviour. \*/     ucLowByte = portCLEAR\_COUNTER\_ON\_MATCH | portPRESCALE\_64;     TCCR2 = ucLowByte;//CTC, CLK/64         /\* Enable the interrupt - this is okay as interrupt are currently globally     disabled. \*/     ucLowByte = TIMSK;     ucLowByte |= portCOMPARE\_MATCH\_A\_INTERRUPT\_ENABLE;     TIMSK = ucLowByte; } /\*-----------------------------------------------------------\*/ #if configUSE\_PREEMPTION == 1     /\*      \* Tick ISR for preemptive scheduler.  We can use a naked attribute as      \* the context is saved at the start of vPortYieldFromTick().  The tick      \* count is incremented after the context is saved.      \*/     void SIG\_OUTPUT\_COMPARE2(void) \_\_attribute\_\_ ((signal, naked));     void SIG\_OUTPUT\_COMPARE2(void)     {         vPortYieldFromTick();         asm volatile ( "reti" );     } #else     /\*      \* Tick ISR for the cooperative scheduler.  All this does is increment the      \* tick count.  We don’t need to switch context, this can only be done by      \* manual calls to taskYIELD();      \*/     void SIG\_OUTPUT\_COMPARE2(void) \_\_attribute\_\_ ((signal));     void SIG\_OUTPUT\_COMPARE2(void)     {         vTaskIncrementTick();     } #endif