multiwii/baseflight — pull request #162 by xeno010 (2014-09-24 20:10:41+00:00)
Title: added function for reading RSSI from a analog singal (with RC-Filter)

Hello,

added function for reading RSSI from a analog singal (RC-Filter)

New Master-Config:
```c
- uint8_t rssi_adc_channel; // Read analog-rssi from RC-filter (RSSI-PWM to RSSI-Analog), RC_CH2 (unused when in CPPM mode, = 1), RC_CH8 (last channel in PWM mode, = 9), 0 to disable (disabled if rssi_aux_channel > 0 or rssi_adc_channel == power_adc_channel)
- uint16_t rssi_adc_max;	// max input voltage defined by RC-filter (is RSSI never 100% reduce the value) (1...4095)
- uint16_t rssi_adc_offset; // input offset defined by RC-filter (0...4095)
````
Tested with Frsky D4R-II

Example for a RC-filter:

PWM-RSSI ___
D4R-II o--|___|-----o-----o RC_CH2/RC_CH8 NAZE32
|
R1 10K |
--- C1
--- 47µF
|

rssi_adc_max = 2950
rssi_adc_offset = 160