Schematic and Expansion Connectors¶
Are you ready to hack your CodeBot?
Here is where you’ll find all the information you need!
Expansion Connectors¶
![../../_images/Expansion-whiskers2.jpg](../../_images/Expansion-whiskers2.jpg)
Note: The two connectors bring out an identical set of signals.
This means that if you make an expansion board that plugs into both connectors, it can be rotated 180° and work the same!
Or, you can make two small boards that each have access to all the expansion pins.
- Mechanical
The connectors are made to line up with standard low-cost prototyping PCBs.
They are 0.1” pitch (spacing between pins)
They are spaced apart 2.4”
![../../_images/Expansion-whiskers1.jpg](../../_images/Expansion-whiskers1.jpg)
- Electrical
I2C bus
SPI bus
UART tx/rx
GPIO / ADC / UART (2)
Regulated 3.3V
Battery voltage (6V when fresh)
(See schematic for details of connection to STM32)
![../../_images/CodeBot_CB2-Expansion.png](../../_images/CodeBot_CB2-Expansion.png)
Software Interface¶
CodeBot CB2 is running version 1.11 of Micropython.
Documentation for using GPIO and many of the internal STM32 hardware peripherals can be found here: http://docs.micropython.org/en/v1.10/library/machine.html
CodeBot CB3 is running CircuitPython. Documentation for that is here: https://docs.circuitpython.org/en/latest/shared-bindings/index.html
The botcore
library documentation has links to the source code which provides examples of using I/O, ADCs, and PWM.
Schematic Diagram¶
(detailed for CB2. See PDF of CB3 below for differences)
A schematic diagram is an electrical engineering drawing that shows all the components and interconnections on a piece of electronic hardware.
- Page 1 highlights
STM32 microcontroller
USB input connector and protection diodes
Dual H-bridge motor driver
Expansion connectors
Speaker
Debug headers
![../../_images/CodeBot_CB2-RevA-1.png](../../_images/CodeBot_CB2-RevA-1.png)
- Page 2 highlights
LED driver shift-registers
USER, LS, and Prox LEDs
Line Sensors
Proximity Sensors
Wheel Encoders
Pushbuttons
Accelerometer
![../../_images/CodeBot_CB2-RevA-2.png](../../_images/CodeBot_CB2-RevA-2.png)
- Page 3 highlights
Power supply
ON/OFF switch
![../../_images/CodeBot_CB2-RevA-3.png](../../_images/CodeBot_CB2-RevA-3.png)