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1925df26ca
Also support FrSky 1khz RSSI. See documentation also added in this commit. This commit also cleans up the PWM mapping code. 'mask' didn't need to be a mask and it wasn't possible to add another 'type' since there were only 4 possible values when it was a mask and they were already defined. Combined with switching to using 16 bits instead of 8 for the mapping configurations, it's now possible to have 256 types instead of 4 at the expense of a few bytes of flash. Moved the RSSI calculation into rx_common.c, previously it was in the main loop.
53 lines
1.3 KiB
Markdown
53 lines
1.3 KiB
Markdown
# RSSI
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RSSI is a measurement of signal strength. RSSI is very handy so you know when you are going out of range or there is interference.
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Some receivers have RSSI outputs. 3 types are supported.
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1. RSSI via PPM channel
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2. RSSI via Parallel PWM channel
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3. RSSI via PWM with PPM RC that does not have RSSI output - aka RSSI PWM
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## RSSI via PPM
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Configure your receiver to output RSSI on a spare channel, then select the channel used via the cli.
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e.g. if you used channel 1 then you would set:
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```
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set rssi_channel = 1
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```
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## RSSI via Parallel PWM channel
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Connect the RSSI signal to any PWM input channel then set the RSSI channel as you would for RSSI via PPM
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## RSSI PWM
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Connect the RSSI PWM signal to the RC2/CH2 input.
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Enable using the RSSI_PWM feature:
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```
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feature RSSI_PWM
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```
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The feature can not be used when RX_PARALLEL_PWM is enabled.
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### RSSI PWM Providers
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When using RSSI PWM it is possible to use standard ~18ms RSSI signals or a faster 1khz/1m RSSI signal.
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The RSSI output on the FrSky X8R (and probably the FrSky X6R) is 1khz.
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To support the 1khz rate enable it via the cli:
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```
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set rssi_pwm_provider = 1
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```
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| Value | Meaning |
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| ----- | ----------- |
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| 0 | ~18ms pulse |
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| 1 | 1ms pulse |
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