Initializing an ADC scan, MCF5213, Codewarrior V5.9.0

[antony_GB]

Hi there.

My problem here is that I am using the codewarrior device initialization bean to set up the ADC. I have not yet experienced any problems when using the 'Device Initialization' tool when using it to setup pins for GPIO. I have included below the exact bean parameters, and the code to write a '1' to the START0 bit of register CNTRL1. Can anyone advise on why a scan will not run? 

-Setting

  Clock Settings

  Clock Divisor select          divide by 8

  ADC Freq                          5MHz

Stop mode 0                        no

Stop mode 1                        no

ADC mode                          Once sequential

Parrallel mode                     Independent  

Trigger mode 0                   Write to START bit only

Trigger mode 1                              "     "

High voltage ref source      External          (AN2 connected to VDDA)

Low voltage ref source      External           (AN6 connected to GND)

-A/D channels

AN0-AN1                            Single ended mode

AN2-AN3                                        "    "

AN4-AN5                                        "    "

AN6-AN7                                        "    "

-sample 0

channel                            AN0

sample                            Enabled

zero crossing                  Disabled

low limit                           0

high limit                         32752                 (highest value before disabling high limit)

-sample 1- 7                  All disabled

-pins 

-AN0                              Enabled

-AN2/Vrefh pin               Enabled

-AN6/Vrefl pin                Enabled

the rest of the pins are disabled

Sync0 and sync1 are both disabled

-interrupts

-conversion complete

interrupt                           INT_ADC_ADCA

request                            Enabled

level                                 7

Priority                             Highest

End of scan interrupt      Enabled

conversion complete interrupt for scanner b is disabled

Zero crossing or limit error

interrupt                      INT_ADC_ADCINT

Request                      Enabled

Level                           7

Priority                        6

Zero crossing             Disabled

Low limit error            Disabled

High limit error           Enabled

-Initialization

Start ADC conversion after Init A         no

         "                "                      B         no

Power down ADC0                              no

    "            "           1                              no

Power down voltage ref                       no

Auto power down                               disabled

power up delay                                  13

Auto stand by                                     disabled

The following code is used to start the scan.

#include "support_common.h"

uint16 Set_START0 = 0;

set_START0 = CNTRL1;

Set_START0 = (uint16)(Set_START0 | CTRL1_START0_BITMASK);

CTRL1 = SetSTART0;

The code compiles, but as far as i can tell, there is no scan being run, and at no point during debug will the program jump to the corresponding end of scan ISR.

Apologies if I have gone a bit over kill on the information included here, I just didn't want to miss out anything that might be important. If anyone has any suggestions, I would be most greatfull. Thanks in advance. Antony

[ProcessorExpert]

Hello,

could you please post here a simple project showing the issue? Are you using some specific EVB board?

best regards
Vojtech Filip
Processor Expert Support Team

[antony_GB]

Hi Processor expert, I have attached  a simple project, although this is not a version of the program i have actually been working on, i knocked this one up quickly to demonstarte how my actual program initializes the ADC scan, and how i want it to use the end of scan interrupt. I do experience the same problem with this program as i do my actual program. All timers and clocks have been set the same. 

[antony_GB]

Just one quick thing, I have changed the interrupt levels, and priorities from those specified in the origonal post.

[ProcessorExpert]

Hello,

I have reproduced the problem.It’s not a problem in generated code but there is missing clearing sequence in handling of PIT interrupt . There is also set the priority of ADC interrupt to lower value than PIT. Due to missing the clearing sequence PIT hangs in handling of the isr – and it cannot be interrupted by ADC because the interrupt has lower priority and it never occurs.

I have corrected your project, please find it enclosed.

best regards
Vojtech Filip
Processor Expert Support Team

[antony_GB]

Thank you for your response ProcessorExpert. I loaded the program you returned. I am still experiencing problems with the handling of interrupts. I cleared the PIF bit where you stated to do so, I then found that my program did generate an interrupt from the ADC, but then the program continued to jump immediately back to the ADC end of scan interrupt. I assumed that this must be due to a similar reason as before, so i cleared the EOSIE0 (interrupt enable) bit at the beginning of the interrupt, and set it again before writing to START0. This did seem to stop the re-calling of the ADC end of scan interrupt, however, since clearing the PIF bit, no further PIT0 timeout interrupts are occuring. I have tried setting the OVW bit, i thought this might jog the PIT back into action, but still there appears to be no activity. Can you advise? Thanks again. Antony

[ProcessorExpert · Accepted solution]

Hello,

I think that the problem is in the ADC´s ISR where there is a neverending loop that causes your program hanging in the isr - see below.

    for(;
    {
        ++count;//this is where i expect my program to end up
    }

Corrected project is enclosed.

best regards
Vojtech Filip
Processor Expert Support Team

[antony_GB]

Amazing, problem solved, and solved. Its so simple, I've just deleted half my code. Thanks alot for the help.  Antony