Removed connection table from README.

As that table is redundant to the schematics.

Author: dhebbeker

README.md

@@ -36,29 +36,27 @@ The CCRP5 is designed such as, the subsystem is only programmed by the manufactu
 
 The main controller should be programmed with a proprietary development environment CCEW32D. Programs must be written in CCBASIC, which is a dialect of the BASIC programming language. The applications are based on a firmware `P5DRIV.S19`. CCBASIC is a low level language. The documentation is available to a limited extent.
 
-This projects aims to control the hardware of the CCRP5 without the CCRP5 microcontrollers. Thus signals from the CCRP5 are tapped and wired to the NodeMCU board.
+This projects aims to control the hardware of the CCRP5 without the CCRP5 microcontrollers.
+Thus an additional "piggyback" PCBA is installed onto the basis CCRP5 PCBA which is tapping into the signals from the CCRP5.
+The piggyback PCBA includes the NodeMCU board.
 
 connections
 -----------
 
-| NodeMCU | ESP8266 | Input        | Output         | CCRP5  | function      | Notes                                                            |
-|---------|---------|--------------|----------------|--------|---------------|------------------------------------------------------------------|
-| D0      | GPIO16  | no interrupt | no PWM nor I2C |        |               | HIGH at boot; used to wake up from deep sleep                    |
-| D1      | GPIO5   | OK           | OK             | D/A 1  | left motor    | often used as SCL (I2C)                                          |
-| D2      | GPIO4   | OK           | OK             | D/A 2  | right motor   | often used as SDA (I2C)                                          |
-| D3      | GPIO0   | pulled up    | OK             |        | I2C 1 SCL     | connected to FLASH button, boot fails if pulled LOW              |
-| D4      | GPIO2   | pulled up    | OK             |        | I2C 1 SDA     | HIGH at boot; connected to on-board LED, boot fails if pulled LOW|
-| D5      | GPIO14  | OK           | OK             | PB3@I2 | right odomenty| SPI (SCLK)                                                       |
-| D6      | GPIO12  | OK           | OK             | PB2@I2 | left odometry | SPI (MISO)                                                       |
-| D7      | GPIO13  | OK           | OK             |        | IO-Exp.1 INTA | SPI (MOSI)                                                       |
-| D8      | GPIO15  | pulled to GND| OK             |        | IO-Exp.1 INTB | SPI (CS); Boot fails if pulled HIGH                              |
-| RX      | GPIO3   | OK           | RX pin         |        |               | HIGH at boot                                                     |
-| TX      | GPIO1   | TX pin       | OK             |        |               | HIGH at boot; debug output at boot, boot fails if pulled LOW     |
-| A0      | ADC0    | Analog Input | X              |        |               |                                                                  |
-
-Table above is adapted from [this reference](https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/#table).
-
-The signals `D/A 1` and `D/A 2` have been disconnected from the pins of the CCRP5's main microcontroller (IC7) because the pins are configured as drain. This interferes with the control of the NodeMCU and causes an 80mA current. The signals have been disconnected by un-soldering and lifting of the microcontroller's pins.
+### Piggyback PCBA
+
+The schematics of the piggyback PCBA are described in `hardware/robot-control-circuit/robot-control-circuit.sch`.
+
+### Basis PCBA
+
+The original schematics can be retrieved at the above mentioned resources.
+
+Some modifications were made to the CCRP5's PCBA.
+The signals `D/A 1` and `D/A 2` have been disconnected from the pins of the CCRP5's main microcontroller (IC7) because the pins are configured as drain (referencing to CCRP5's schematics).
+This interferes with the control of the NodeMCU and causes an 80mA current.
+The signals have been disconnected by un-soldering and lifting of the microcontroller's pins.
+
+Also the IO-expander `I11` has been disconnected in order to be able to control the current for the IR-LEDs `D3` and `D4`.
 
 Software
 ========