S4A is a powerful platform to learn programming Arduino but by default it can’t be interfaced with Adafruit Motor Shield. I have rewritten S4A firmware in order to achieve this goal.
You can download firmware from here.
I have tested it on Arduino UNO and this shield.
https://www.adafruit.com/products/1438
This is the relationship with S4A variables and Adafruit Motor Shield outputs:
| S4A | Adafruit Motor Shield |
| Analog 5 | Speed DC Motor 1 |
| Analog 6 | Speed DC Motor 2 |
| Digital 10 | Direction DC Motor 1 (HIGH = FRONT) (LOW = BACKWARD) |
| Digital 11 | Direction DC Motor 2 (HIGH = FRONT) (LOW = BACKWARD) |
| Digital 7 | PWM Servomotor 1 |
| Digital 8 | PWM Servomotor 2 |
For compiling this firmware you will need Adafruit Motor Shield Library. It can be downloaded from Adafruit website:
https://learn.adafruit.com/adafruit-motor-shield-v2-for-arduino/install-software