[ARM] LPC2148 Reset Problem

[praveen_balu]

Hi, i had built a circuit of LPC2148 Development Board, which uses FT232RL to download the program through USB, I am unable to find out whats the problem is all about, everything is going fine including downloading the hex file to the controller, but after the hex file is downloaded, the program is not getting executed automatically, also when i press the reset button also the program is not executing, however if i switch off and switch on the board twice or thrice, the programs runs. what may be the problem ???

I have attached the circuit below, all the grounds are made common in the circuit.

 

[salmanliaquat]

At BOOTUP LPC2148 polls P0.14(PIN 41). If the pin is low (grounded) the controller enters in boot-loader mode and accepts programming commands on UART0. If the pin is high, the controller jumps to the program (if any valid program is present in flash).
I cannot see any thing connected to P0.14 in you circuit. So please elaborate how r you getting it programmed using FT232.

 

[ftsolutions]

+1 with what salmanliaquat says - you should put a pullup resistor to +Vcc on P0.14 in order for the processor bootloader to start your user code. The pin is left floating, so it is somewhat random whether it will be read as "1" or "0" when the bootloader samples its value. Plus, there are certain other exceptions that you might be creating with your power cycling that can cause it to run.

You should read the user manual, page 296, specifically, for more information on this

 

[praveen_balu]

View attachment ARM_SCHEMATIC.pdf

At BOOTUP LPC2148 polls P0.14(PIN 41). If the pin is low (grounded) the controller enters in boot-loader mode and accepts programming commands on UART0. If the pin is high, the controller jumps to the program (if any valid program is present in flash).
I cannot see any thing connected to P0.14 in you circuit. So please elaborate how r you getting it programmed using FT232.

Hi salmanliaquat, i forgot to mention in my previous post about that P0.14 is not connected in the schematic, for the same i have connected the external jumper wire for that connectivity. I am entering into boot-loader mode by pressing reset switch and isp switch together and then release reset switch and then isp switch by this i am entering into the boot loader of the controller and programing the hex file into the controller.

 

[salmanliaquat]

....for the same i have connected the external jumper wire for that connectivity.

For what connectivity ? you have connected the P0.14 to which point in the schematic.
Redraw the updated schematic and upload if you really want any help.