topic Problem in implementation of SNMP Protocol with LPC1768 in LPC Microcontrollers

Problem in implementation of SNMP Protocol with LPC1768

pvgidveer — Thu, 24 Sep 2020 03:48:02 GMT

Hello everyone,

As mentioned in subject, I am working on a project in which SNMP protocol is to be implemented. I have written a code for SNMP Protocol which is working fine with the LPC1768 controller board. I am able to receive all the data(string) which is sent from controller to PC using ethernet. These strings are written in MIB_STR() function of MIB Table,

for eg.

const MIB_ENTRY snmp_mib[] = {

/* ---------- System MIB ----------- */

/* SysDescr Entry */
{ MIB_OCTET_STR | MIB_ATR_RO,
8, {OID0(1,3), 6, 1, 2, 1, 1, 1, 0},
MIB_STR("Hello World"), //as this string i am not updating while execution of main function so it is working fine
NULL }

};

but when i am trying to update current values of parameters in place of string, it is not allowing to do that.

for eg.

const MIB_ENTRY snmp_mib[] = {

/* ---------- System MIB ----------- */

/* SysDescr Entry */
{ MIB_OCTET_STR | MIB_ATR_RO,
8, {OID0(1,3), 6, 1, 2, 1, 1, 1, 0},
MIB_STR(Temp[1]), //error: initializer element is not a compile-time constant
NULL }

};

Temperature values are saved in an array in ASCII format.

so, I am planning to Copy the same MIB Table to RAM when controller starts execution of code & then i want controller to read MIB table from the specific RAM address area so, i can update Current values of parameters at respective RAM Address locations.

may i know how to make controller to read from Specific RAM address location instead of FLASH memory while execution of main function.

Has anyone encountered this issue or maybe even found a solution?

Thank you.

Regards,

Pruthviraj Gidveer.

Re: Problem in implementation of SNMP Protocol with LPC1768

xiangjun_rong — Thu, 24 Sep 2020 05:36:14 GMT

Hi, PvgidVeer,

Can you tell us the tools you are using? is the MIB_STR(Temp[1]) a function or macro? do you have it's prototype?

XiangJun Rong

Re: Problem in implementation of SNMP Protocol with LPC1768

pvgidveer — Thu, 24 Sep 2020 06:10:52 GMT

Hello, Xiangjun_rong,

I am using Keil uVision 4 IDE and MIB_STR() is declared as a macro in Net_Config.h file

macro declaration in Net_Config.h is as given below.

/* SNMP-MIB Macros */
#define MIB_STR(s) sizeof(s)-1, s

Thanks & Regrads,

Pruthviraj Gidveer.

Re: Problem in implementation of SNMP Protocol with LPC1768

xiangjun_rong — Fri, 25 Sep 2020 09:21:15 GMT

Hi,

Unfortunately, I do not see the Net_Config.h file in the LWIP directory, can you post all the project to the community so that we can have a review.

XiangJun Rong

Re: Problem in implementation of SNMP Protocol with LPC1768

pvgidveer — Mon, 05 Oct 2020 10:55:45 GMT

Hi everyone,

Here i have attached a code, If you compile this code you will get an error, to resolve that error goto line no.49 of SNMP_MIB.c file & do modifications as mentioned in commented line then it will work. but actually i want to print the values of which are stored in dataString[]. If i try to print values from the array dataString[] it will give an error. Help me to resolve this problem.

Thanks & regards,

Pruthviraj Gidveer.