Can we remove sleep crstal(32.768kHz) if BLE do not enter sleep mode?

Chanho No

Intellectual 790 points

Other Parts Discussed in Thread: CC2540, CC2640

Hello,

I know that sleep crystal is needed for BLE Certification(SIG).

https://e2e.ti.com/support/wireless_connectivity/bluetooth_low_energy/f/538/t/258847

The sleep crystal is removed on the CC2540 USB dongle design,

Can we remove external sleep crstal(32.768kHz) if BLE do not enter sleep mode? We should progress BLE Certification.

(CC2540 or CC2640)

Thanks.

over 9 years ago

0 Eirik V over 9 years ago

TI__Guru 56590 points

Hello Chanho,

Yes, for the CC254x as long as you disable sleep/power modes and the high speed crystal oscillator is always running you do not need the low speed external crystal.

On CC2640 PG2.3 silicon or later you can actually run on the low speed 32 kHz RCOSC and enable power saving, read more about crystalless mode in this App Note:

Running Bluetooth® Low Energy on CC2640 Without 32 kHz Crystal

Bluetooth®︎

Bluetooth forum

Can we remove sleep crstal(32.768kHz) if BLE do not enter sleep mode?