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How to change Data rate and modulation format in cc2541

Biswa Ranjan Nayak
Prodigy 235 points

Other Parts Discussed in Thread: CC2541, CC2541-Q1

Hi 

We are currently using the TI's BLE stack on one of our custom board based on cc2541 processor. Now for some requirements I need to change the modulation speed and format in the firmware. The required speeds are 

1. 250 kbps, GFSK, 160-kHz

2. 250 kbps, MSK

Now, as per the spec http://www.ti.com.cn/cn/lit/ds/symlink/cc2541-q1.pdf both of those speeds and mode are supported by the chip/RF. 

I also checked the phy.h file in the stack and found that all those speeds/modes are supported as below

#define PHY_MOD_NO_TONE 0x04
#define PHY_MOD_GFSK_250KHZ_1MBPS_TONE 0x24
#define PHY_MOD_GFSK_156KHZ_250KBPS_TONE 0x28
#define PHY_MOD_GFSK_156KHZ_1MBPS_TONE 0x2C
#define PHY_MOD_MSK_250KBPS_TONE 0x30
#define PHY_MOD_MSK_500KBPS_TONE 0x32
#define PHY_MOD_MSK_1MBPS_TONE 0x34

But the problem is I could not find any APIs anywhere to set or change these values. For that matter no where in the BLE stack are these used. 

Is there a way that I can change the speeds and modes?

Thanks in Advance

  • 0
    TI__Genius 17975 points

    The BLE stack only operates in a BLE compliant mode, in which the radio modulation is 1Mbps GFSK as defined in the BT 4.0 core specification.

    If you want to use a different modulation, you will need to use the device in proprietary (non-BLE) mode. You can find sample code for using CC2541 in proprietary mode here (under "software"): http://www.ti.com/product/CC2541/toolssoftware