CC1311P3: Pre amble / Sync word disable provision

Hi Theiv,

What you are asking about in this thread is quite advanced features/not commonly used. We have the most detailed documentation for our radio in the Technical reference manual. I will advise you to take a look to see what's supported and not.

https://www.ti.com/lit/swcu191 

1. This is not really supported. You can see our basic preamble and syc word configuration options if you open SmartRF studio and select your device.

2. I'm not sure what you mean. Are you talking about excluding postamble from crc?

3. You can send packets with variable packet length. However I'm not sure if this covers your need?

Cheers,

Marie H

Hi Theiv,

1. Why do you want to disable preamble and sync word? They are there to help the radio tune in on a packet.

If this is a legacy protocol compatibility case, we might be able to help you adjust the parameters if you can post the packet format.

2. Yes.

3. Yes you can set the packet length field to 0. I would advise you to do some testing on packet length, if you just continue sending bytes your radio may drift, there will eventually be bit errors etc.

Cheers,

Marie

Minimum supported preamble length is 1 bit (can be 1 or 0) , and minimum sync word length is 8 bits.

CRC can be disabled.

If you want to send a packet with 12 x 0x7F + payload this can be achieved in the following way:

The preamble is configurable with an override, so after using sysConfig to generate you settings, you need to add the ti_radio_config .c file manually to your project, and exclude the SysConfig generated file from the build.

In the ti_radio_config.c file, change the following:

uint32_t pOverridesTxStd[] =
{
    // override_txstd_placeholder.json
    // TX Standard power override
    TX_STD_POWER_OVERRIDE(0x013F),
    // The ANADIV radio parameter based on LO divider and front end settings
    (uint32_t)0x11310703,
    // override_phy_tx_pa_ramp_genfsk_std.json
    // Tx: Configure PA ramping, set wait time before turning off (0x1A ticks of 16/24 us = 17.3 us).
    HW_REG_OVERRIDE(0x6028,0x001A),
    // Set TXRX pin to 0 in RX and high impedance in idle/TX. 
    HW_REG_OVERRIDE(0x60A8,0x0401),
    
    (uint32_t)0xFEFE0043, // Modified: Preamble = 0x7F (0xFE sent LSB first)
    
    (uint32_t)0xFFFFFFFF
};

// CMD_PROP_TX
// Proprietary Mode Transmit Command
rfc_CMD_PROP_TX_t RF_cmdPropTx =
{
    .commandNo = 0x3801,
    .status = 0x0000,
    .pNextOp = 0,
    .startTime = 0x00000000,
    .startTrigger.triggerType = 0x0,
    .startTrigger.bEnaCmd = 0x0,
    .startTrigger.triggerNo = 0x0,
    .startTrigger.pastTrig = 0x0,
    .condition.rule = 0x1,
    .condition.nSkip = 0x0,
    .pktConf.bFsOff = 0x0,
    .pktConf.bUseCrc = 0x0, // Modified: Disable CRC
    .pktConf.bVarLen = 0x0, // Modified: Fixed Packet Length mode
    .pktLen = 035, // Modified: Packet length (the length of the 4 last 0x7F + the payload
    .syncWord = 0x7F7F7F7F, // Modified: 0x7F, byte 5 to byte 8
    .pPkt = 0
};

With these settings, you will send 4 bytes of 0x7F as preamble, 4 bytes of 0x7F as sync word, and then you have to add the last 4 bytes of 0x7F, as the 4 first byte of your packet.

BR

Siri

Hi,

fdev of +/- 4.25 kHz is possible.

Thanks,

  Richard

Hi,

Why do you need an 8th order LPF ?

Just follow the standard ref design which is sufficient to pass regulations. Any additionally filtering will add margin to the harmonics but also increases IL.

Please follow the 433 MHz ref design.

Hi,

If your end customer states that they must have an 8th order LPF, then it might be better to use a SAW filter instead. 

If there is a strict requirement for an 8 th order LPF then you would need to add an additional LC filter to the standard ref design. 

It is a strange requirement specifying the order of the LPF since this is dependent on the PA topology. 

Hi,

since it's one of the legacy systems we have this requirement. We will add an external SAW filter for better performance as suggested.