Added some more doc

README.md

@@ -16,22 +16,34 @@ __Powering:__ The Pecan Pico 10 can be powered either by USB or by a single LiPO
 
 __Storage:__ There can be stored up to 14,560 data points (GPS & telemetry) without any external memory devices. For additional storage and picture logging, a Micro SD card can be inserted into the device.
 
-__Transceiver:__ Though the software is mainly optimized for APRS operation, it can be also used for 2/4FSK (RTTY) and OOK (CW) operation. The maximum transmission power is 100mW. The fastest tested FSK speed is 115k2.
+__Transceiver:__ Though the software is mainly optimized for APRS operation, it can be also used for 2/4FSK (RTTY) and OOK (CW) operation. The maximum transmission power is 100mW. While the transceiver has ony a signle LPF, it is only able to operate on one frequency band (either 2m or 70cm). The inductors/capacitors in the schematic are adjusted to the 2m amateur radio band, but with different components it can be used on the 70cm band too. The fastest tested 2FSK transmission speed is 115k2. While the Pecan can transmit AFSK and 2FSK, it is only able to receive AFSK APRS. It is possible to receive 2FSK APRS too, although the software hasn't been implemented yet.
 
-__Image transmission:__ The software makes use of the JPEG compression of the Omnivision OV5640. Although the connector is suitable for some other cameras too, the OV5640 is the only camera which can be used due to the missing HREF pin. The protocol being used for the images transmission is APRS/SSDV. This protocol is fully APRS compatible but needs extra software to be decoded again. Though the camera can do pictures up to 5MP, there is only enough memory available to take XGA pictures (1024x768px).
+__Image transmission:__ The software makes use of the JPEG compression of the Omnivision OV5640. Although the connector is suitable for some other cameras too, the OV5640 is the only camera which can be used due to the missing HREF pin. The protocol being used for the images transmission is APRS/SSDV. This protocol is fully APRS compatible but needs extra software to be decoded again which is included in this project. Though the camera can do pictures up to 5MP, there is only enough memory available to take XGA pictures (1024x768px).
+TODO: Precise description about APRS/SSDV
 
-__Telemetry transmission:__ Since APRS does only allow a ceirtain amount of telemetry fields being transmitted, the complete telemetry is sent as a binary format along with the position transmissions in the comment field. The APRS packet stays completly compatible with the existing network. The additional telemetry can be decoded with an additional software.
+__Telemetry transmission:__ Since APRS does only allow a ceirtain amount of telemetry fields being transmitted, the complete telemetry is sent as a binary format along with the position transmissions in the comment field. The APRS packet stays completly compatible with the existing network. The additional telemetry can be decoded with an additional decoder which is included in this project. It is the same decoder  which decodes APRS/SSDV too. The software is currently running on [this website](http://www.wlankabel.com).
 
-__Sensors:__ The Pecan uses a single chip (BME280) to measure the temperature, airpressure and humidity. There can be attached up to two additional BME280's for various purposes.
+__Sensors:__ The Pecan uses a single chip (BME280) to measure the temperature, airpressure and humidity. There can be attached up to two additional BME280's for various purposes like internal and external temperatures. You may want to have an external sensor while the internal sensor on the PCB is influenced by the heat generated by the components. The difference can vary between 2 and 10°C.
 
-__Additional sensors:__ The Pecan provides an external I2C bus from where addional sensors can be accessed. There is also a signle GPIO pin, which can be used for varios stuff.
+__Additional sensors:__ The Pecan provides an external busses (I2C and UART) from where addional sensors can be accessed. On the 10a variant is a signle GPIO pin, which can be used for varios stuff. There can either be I2C or UART be used on the 10a variant while I2C shared the same pins as UART does. In the 10b variant the additional GPIO pin has been removed, therefore I2C and UART are now separate. If you have no need for UART/I2C, those pins can be also used as normal GPIO's.
 
-__GNSS (GPS):__ The ublox EVA-7M chip can receive GPS which is used to determine the region specific APRS frequency. Since the GPS draws a lot of power, it can be switched on and off as needed. The device is also compatible with the ublox EVA-M8.
+__GNSS (GPS):__ The ublox EVA-7M chip can receive GPS which is used to determine it's location and the region specific APRS frequency. Since the GPS draws a lot of power, it can be switched on and off as needed. The device is also compatible with the ublox EVA-M8 which can receive GLONASS, Beido and Galileo too.
 
-__Debugging/Configuration:__ The device can be accessed over USB in order to configure it or get debug messages out of the device. The log memory can also be accessed over USB.
+__Debugging/Configuration:__ The device can be accessed over USB (serial terminal) in order to configure it or get debug messages out of the device. The log memory can also be accessed over USB.
 
 __Schematic:__ Here we go! [Download](https://raw.githubusercontent.com/DL7AD/pecanpico10/master/tracker/hardware/pico/output/pecanpico10.pdf)
 
+__Operation variants__
+- Car/Balloon Tracker
+- Digipeater
+- Weather station (software not implemented yet)
+- Image transmitting device
+All variants can be combined with each other
+
+__Software Manual__
+TODO: How to access it through USB
+TODO: How to configure the device
+
 __More:__ *Flashing the chip (link missing)*
 
 # Transmitted test pictures

powering.md

@@ -2,18 +2,22 @@
 
 The Pecan can be either powered by following power sources. The power consumption is around 50mW in sleep mode and around 200mW at normal operation. If the transmitter is constantly transmitting, the tracker consumes around 500mW.
 
-There are two power inputs which can be accessed from the 100mil-pinheader and one by USB. Solar cells are connected to pin 1 and 2. The battery is connected on the backside to the BATT_CONN and GND pad. While the battery is physically connected to the curcuit board, it's not directly connected to the circuit itself unless a jumper is connected between pin 3 and 4. Alternatively the battery can be connected to pin 4 and 15.
+There are two power inputs which can be accessed from the 100mil-pinheader and one by USB. The solar cells must be connected to pin 1 and 2. The battery is connected on the backside to the BATT_CONN and GND pad. While the battery is physically connected to the circuit board, it's not directly connected to the circuit itself unless a jumper is connected between pin 3 and 4. Alternatively the battery can be connected to pin 4 and 15.
 
-The circuit can also be powered externally by USB.
+## Battery disconnect by USB
 
-Note: Due to an error in the design of the Pecan Pico 10a, the battery must not be connected when USB is applied. You may connect USB and battery at the same time, if D1 and Q1 are removed.
+The circuit can also be powered externally by USB. In this case, the battery is disconnected from the circuit by Q1 and the circuit is only powered by USB. This means, that the battery can also not be charged by the solar cell. This particular design has been implemented to be used on a rocket. The circuit should be powered by the carrier rocket until the payload is being ejected in order to have full battery capacitance at the ejection event.
+
+Note: Due to an error in the design of the Pecan Pico 10a, the battery must not be connected when USB is applied. You may connect USB and battery at the same time, if D1 and Q1 are removed. This bug has been fixed in the 10b variant and can be used as intended now.
 
 ## USB
 USB can be used for operation at the computer. You may connect a battery to the battery input. Once USB is connected, the battery gets disconnected and the tracker is only powered over USB. Once USB is disconnected, the tracker is powered from the battery again. This feature is archived by a MOSFET and doesn not need any software cooperation.
 
 ## 3x Alkaline or Lithium Batteries
-If you have only a time limited operation planned, you might want to use primary batteries. The tracker needs at least 1.8V in order to operate. In order to use the camera it needs at least 3.3V. So the tracker can be powered from three AA or AAA serial connected batteries from the +VBAT input.
+If you have only a time-limited operation planned, you might want to use primary batteries. The tracker needs at least 1.8V in order to operate. The camera needs at least 3.3V. So the tracker may be powered by three AA or AAA serial connected batteries from the +VBAT input. Note: You must not attach a solar cell while the tracker would try to charge it.
 
 ## A signle LiPO cell and solar cells
-If a long operation is required, the tracker can be powered by a LiPO or LiIon battery. The battery can be charged by Solar cells from the +VSOL input. The tracker may also be operated with solar cells only.
+If a long operation is required, the tracker can be powered by a LiPO or LiIon battery. The battery can be charged by solar cells from the +VSOL input. The tracker may also be operated with solar cells only.
 
+
+TODO: Power scheme missing