CC2541: BLE stack, Key handling

Gytis Kazlauskas

Part Number: CC2541

Hello,

I am using 2541 BLE stack SimplePeripheralExample. I am trying to detect a signal on my P0_0 pin and increase a counter int i = 0; which i am sending over BLE to my phone. The signal i am trying to detect is 3.3V which is HIGH for 3micro seconds.(added the picture below). For signal detection i am using simpleBLEPeripheral_HandleKeys which i adopted to my application. The problem i am facing is that if i trigger the pin manually by hand with 3.3V it detects and sends incremented number to my phone, but since i try with this signal coming from my sensor it cannot detect.

I tried to minimize HAL_KEY_DEBOUNCE_VALUE to 0 and turn of POWER_SAVING but that did not helped. I am not sure where can be the problem. Maybe someone can help me and tell me how to debug in order to find the problem. Thank you.

Kind regards,

Gytis

over 6 years ago

0 YiKai Chen over 6 years ago

Guru 735685 points

Set a breakpoint inside HAL_ISR_FUNCTION( halKeyPort0Isr, P0INT_VECTOR ) to check if it hits first. If not, you should check your register configuration for P0.0 interrupt.

0 Gytis Kazlauskas over 6 years ago in reply to YiKai Chen

Prodigy 100 points

I did as you suggested me and when i trigger the pin with 3.3V manually it hits HAL_ISR_FUNCTION( halKeyPort0Isr, P0INT_VECTOR ) but since i connect to my signal from the sensor it miss the interrupt

0 YiKai Chen over 6 years ago in reply to Gytis Kazlauskas

Guru 735685 points

Do you use scope to check signal on P0.0 when you connect it to your sensor? If yes, do you see edge change from your sensor?

0 Gytis Kazlauskas over 6 years ago in reply to YiKai Chen

Prodigy 100 points

If I connect oscilloscope to P0_0 and sensor i see that the voltage is dropped to around 1.6V (picture below)

0 YiKai Chen over 6 years ago in reply to Gytis Kazlauskas

Guru 735685 points

Why the high/low delta is only 1.6V? I suppose there’s something wrong on your sensor output voltage.

0 Gytis Kazlauskas over 6 years ago in reply to YiKai Chen

Prodigy 100 points

I cannot answer why it drops to 1.6V, but when i measure my sensor output with oscilloscope without cc2541 connected it's 3.3V.

0 YiKai Chen over 6 years ago in reply to Gytis Kazlauskas

Guru 735685 points

Since it drops to 1.6V when you measure it, I suppose there’s something wrong in your circuit. I suggest you to debug your HW to find out the problem first.

0 Gytis Kazlauskas over 6 years ago in reply to YiKai Chen

Prodigy 100 points

I found a problem related to voltage drop, it was incorrectly configured port instead of input it was output. I fixed it. (P0DIR = 0xFF instead of P0DIR = 0xFC;).

After fixing this problem the interrupt gets hit by my signal but not every time.

Since my signal period T = 300 micro seconds (lowest) i would like to fire interrupt in 3.33kHz frequency, which means that every 0.0003 s. interrupt would be fired and value would be increased of my integer.

1) What would be the maximum frequency for firing interrupt caused by external signal?

2) What would have higher priority and can cause missed interrupt on my external signal?

0 YiKai Chen over 6 years ago in reply to Gytis Kazlauskas

Guru 735685 points

Do you mean to do pulse count from GPI pin?

0 Gytis Kazlauskas over 6 years ago in reply to YiKai Chen

Prodigy 100 points

Yes.

0 YiKai Chen over 6 years ago in reply to Gytis Kazlauskas

Guru 735685 points

Try to refer to discussions in e2e.ti.com/.../1717084

Bluetooth®︎

Bluetooth forum

CC2541: BLE stack, Key handling