Apparently Wire library is not accepting any more data unless the buffer received from the previous i2c operation is completely read from! Since it's hard to debug an onReceive/onRequest handler via a Serial console (merely because doing Serial operations in an interrupt handler is impossible), I had to look through the Arduino libraries code trying to guess what's going on.Īfter a while I found a set of instructions that looked suspicious. It was bothering me for a while until I decided to figure it out yesterday. In practice it is seen as if an Arduino gets stuck sending -1 to whatever request it receives. All Arduinoes are operating in slave mode, the bus master is a Raspberry Pi board.įor this apparently you have to install both onReceive and onRequest handlers the 'write' operation is simply handled by onReceive by receiving the register and immediately after that a new value the 'read' is a bit more complicated, as onReceive receives the register from the wire, and then onRequest that follows needs to send the data.Īll that works quite fine until the speed at which Raspberry Pi queries the Arduinoes is skyrocketing to where Wire library apparently gets confused. If(!display.So I was implementing an i2c slave on the Rover's Arduinoes the one that could be read from and written to. SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally Static const unsigned char PROGMEM logo_bmp = #define NUMFLAKES 10 // Number of snowflakes in the animation example #define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)Īdafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET) Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)

#define SCREEN_HEIGHT 64 // OLED display height, in pixels #define SCREEN_WIDTH 128 // OLED display width, in pixels BSD license, check license.txt for more information All text above, and the splash screen below must be included in any redistribution. Written by Limor Fried/Ladyada for Adafruit Industries, with contributions from the open source community. This example is for a 128x32 pixel display using I2C to communicate 3 pins are required to interface (two I2C and one reset).Īdafruit invests time and resources providing this open source code, please support Adafruit and open-source hardware by purchasing products from Adafruit! Pick one up today in the adafruit shop! -> This is an example for our Monochrome OLEDs based on SSD1306 drivers. The following code should load: /*********

Wire h arduino library