gpio & ISP mode problem in LPC1768

[aliesna]

HI;

I use LPC 1768. Unfortunately P2.10 is not working and is in low level. therefor microcontroller goes to the ISP mode and not be programmed with jlink.

Is there a way to disable ISP mode?

thanks for your help.

[lpcxpresso_supp]

If P2.10 is active low at reset, the ISP is entered. It's supposed to work this way. You didn't provide details of the EINT0 circuit. Are you sure there's nothing pulling this pin down? And, if this were the case, EINT0 would be useless to you. These pins are 5V tolerant, but they can be damaged.

Thanks and regards,

MCUXpresso Support

[aliesna]

yes, i'm sure. I don't connect P2.10 nowhere at all.

I don't use P2.10 as EINT0 in my program now and turn on internal pull-up resistor. but this happen yet.

[lpcxpresso_supp]

Review this FAQ if you haven't done so:

Design Considerations for Debug

[Carlos_Mendoza]

Hi Ali,

What do you mean when you say the P2.10 pin is not working? You should not have problems programming the device if it enters ISP mode.

The only way to disable the ISP functionality is by setting the CRP level to 3, but this means there is no way to update the user flash, which means no further code updates are possible. You can find detailed information about on this link:

https://community.nxp.com/thread/388854 

Hope it helps!

Best Regards,
Carlos Mendoza
Technical Support Engineer

[aliesna]

Thanks a lot Mr engineer 

I used P2.10 as EXTINT0 in a program. When i was working with it went to low level and didn't change anymore.

Now when i try to download any program with keil by jlink and JTAG this error is showing:

CPU did not halt after bootloader

I read back flash memory with jlink. programs will be downloaded but will not run.

I searched in internet and I understood that it is because of ISP mode.

[Carlos_Mendoza]

Hi Ali,

Please make sure that the P2.10 is pulled up on startup, otherwise the ISP mode will be entered instead of running the program.

Hope it helps!

Best Regards,
Carlos Mendoza
Technical Support Engineer

[aliesna]

Hi Mr Engineer

thanks for your answer 

P2.10 in startup is pulled up but in hardware is in low level.

is there any way that avoid entering ISP mode except CRP3?

[lpcxpresso_supp]

The ISP is a bootloader feature mostly used for programming. The ISP is entered upon reset if the ISP line is active low. Thereafter, it will loop in the ISP only if the bootloader determines there is no valid flash image present (as calculated by the checksum word). Section 32.3 of the LPC176x/5x User manual (UM10360.pdf) covers the P2.10 operation. On external reset, watchdog reset, power on reset, and brown out detect (BOD), the PINMODE4 registers are set to zero. This suggests P2.10 has an internal pull-up resistor at reset. It's unclear whether your board incorporates a pull-down or pull-up resistor. Since you're using P2.10 for EINT0, you need to review the hardware circuit.

Thanks and regards,

MCUXpresso Support

[aliesna]

This happens in any program. I turned on internal pull-up resistor and didn't use P2.10 this happened again.

This massage in keil showed again and program didn't run:

cpu did not halt after bootloader

I also measured voltage of P2.10 that was 0 volt.

I think P2.10 is ruined because it is not working in any programs and is always in low level.

is there any way that avoid entering ISP mode??