CC1101: Programming CC1101 for 345 MHz ASK

According to the datasheet, CC1101 supports 345 MHz. See datasheet/ SmartRF Studio on how to set the frequency and modulation format.

Start bits, does that mean you have preamble + sync? If not, you have to use async mode to receive this format.

It definitely has sync bits and CRC, i.e 1 byte high low high low. Also is manchester encoded. Would a preamble be a couple of extra long bits, i.e. the highs and lows are longer in the preamble than in the rest? Does the CC1101 have to be configured to wait for the preamble?

I found a screenshot, and actually it looks like it starts with the sync bits:

For old UART protocols, 1 byte was used as start/ stop, typically as a manchester violation.

CC1101 needs a 4 byte preamble ('..010101...' pattern) and at least a 16 bit sync word with good auto correlation to be able to receive a signal with good performance. Since this is a old protocol without this, you should look into async mode, see 27.1 in www.ti.com/.../cc1101.pdf

FREQ2 0D

FREQ1 44

We don't have any example code for async mode, you have to develop code to do this your self. What you would need to do is to oversample the pin at least with a factor 3 (to avoid glitches etc), do a majority vote on the result and then search for the start bit.

For the settings, start from the OOK setting that is predefined in Studio, adjust if needed according to www.ti.com/.../swra215e.pdf and change the frequency. Then do a register export since you need to set more registers than the ones you have listed here.

Let's call my code for listening the decoder. Would the decoder continuously read the pin, looking for the start pattern?

For example, would reading the pin with no message sent return 000 000 000 000 000 000 000 000, etc? Here each bit is sampled 3 times, though in practice this would be larger and dependent on the sample rate.

When a signal like 000 000 111 000 111 000 111 is received, would the decoder convert the samples to bits 0 0 1 0 1 0 1, and then look for a start pattern?

Thanks for the screenshot. I understand how the export works now. It is very convenient.

Regarding the decoder software, does this sound right? The decoder continuously read the pin, looking for the start pattern. For example, when reading the pin with no message sent, the decoder would receive 000 000 000 000 000 000 000 000, etc. Here each bit is sampled 3 times, though in practice this would be larger and dependent on the sample rate. When a signal like 000 000 111 000 111 000 111 is received, the decoder would convert the samples to bits 0 0 1 0 1 0 1, and then look for a start pattern.

Sounds correct.