Hello, I have a working LPC1758 MDK-arm 4 program that is based on the HID example.
When I set the systick to 1ms or less USB enumination fails. At 10ms all is fine, I need 1 ms for other a2d tasks.
Any ideas?
I see this example did not use the RTOS C:\Keil_v5\ARM\Boards\Keil\MCB1700\RL\USB\Device\HID\
But if you are adjust hte systick it sounds like you may be.
If you adjust the Systick time, are you also modifying the Timer tick value [us] in the RTX_conf_CM.c
http://www.keil.com/support/man/docs/rlarm/rlarm_ar_cfgtimer.htm
Did you check the PLL, USB clock configuration settings in the system_LPC17xx.c file? Especially USBCLKCFG_Val?
Double check all clock settings - timing is critical in USB applications.
also, when debugging your application , make sure to check the Peripherals -> System Viewer -> USB window to see the USB register values.
You can adjust the systick while running your code using the Peripherals -> Core Peripherals-> Systick timer.
That way you don't have to recompile your project every time while fiddling with timings.
Thank you for your help. It looks as if tasks were "nose to tailing" and the usb was not getting in Increasing the systick by 5% fixed it