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Adafruit seesaw Created by Dean Miller https://learn.adafruit.com/adafruit-seesaw-atsamd09-breakout Last updated on 2022-07-18 06:33:11 PM EDT ©Adafruit Industries Page 1 of 39 Table of Contents Overview 5 Pinouts 7 • • • • • • • • • Power Pins: Logic Pins: GPIO Pins: Neopixel Pins: Address Pins: ADC Pins: PWM Pins: Interrupt Pins: Programming Pins: Arduino Wiring & Test • • • • • 9 Arduino Wiring & Test I2C Wiring Download Adafruit_Seesaw library Load Test Example Documentation CircuitPython Wiring & Test 12 • CircuitPython Wiring & Test • I2C Wiring • Download Adafruit_CircuitPython_Seesaw library Python Docs 14 Raspberry Pi Wiring & Test 14 • • • • • Install Python Software Enable I2C Run example code Documentation Full Example Code Using the Seesaw Platform 19 Reading and Writing Data 19 • • • • Setting the Device Address I2C Transactions Writing Data Reading Data GPIO • • • • • • • • 21  Function Registers GPIO register setup on SAMD09: GPIO register setup on ATTiny8x7: DIRSET (0x02, 32 bits, Write Only) DIRCLR (0x03, 32 bits, Write Only) GPIO (0x04, 32 bits, Read/Write) SET (0x05, 32 bits, Write Only) CLR (0x06, 32 bits, Write Only) ©Adafruit Industries Page 2 of 39 • • • • • • TOGGLE (0x07, 32 bits, Write Only) INTENSET (0x08, 32 bits, Write Only) INTENCLR (0x09, 32 bits, Write Only) INTFLAG (0x0A, 32 bits, Read Only) PULLENSET (0x0B, 32 bits, Write Only) PULLENCLR (0x0C, 32 bits, Write Only) Analog to Digital Converter • • • • • • • • • • • • • • 26 SAMD09 ADC channels are: ATtiny8x7 ADC channels are: Function Registers STATUS (0x00, 8bits, Read Only)   INTENSET (0x02, 8bits, Write Only) INTENCLR (0x03, 8bits, Write Only) WINMODE (0x04, 8bits, Write Only) WINTHRESH (0x05, 32bits, Write Only) CHANNEL_0 (0x07, 16bits, Read Only) CHANNEL_1 (0x08, 16bits, Read Only) CHANNEL_2 (0x09, 16bits, Read Only) CHANNEL_3 (0x0A, 16bits, Read Only) CHANNEL_20 (0x1B, 16bits, Read Only) Interrupts 30 NeoPixel 31 • • • • • • Function Registers PIN (0x01, 8bits, Write Only) SPEED (0x02, 8bits, Write Only) BUF_LENGTH (0x03, 16bits, Write Only) BUF (0x04, 32 bytes, Write Only) SHOW (0x05, no args, Write Only) EEPROM 32 • Function Registers • SAMD09 • ATtiny817 PWM 33 • Function Registers • PWM_VAL (0x01, 16bits, Write Only) UART • • • • • • 35 Function Registers Status (0x00, 8bits, Read Only) INTEN (0x2, 8bits, Read/Write) INTENCLR (0x03, 8bits, Write Only) BAUD (0x04, 32bits, Read/Write) DATA (0x05, 32bytes, Read/Write ) Downloads 37 • Documents • Schematic • Dimensions ©Adafruit Industries Page 3 of 39 Documentation ©Adafruit Industries 39 Page 4 of 39 Overview Adafruit seesaw is a near-universal converter framework which allows you to add and extend hardware support to any I2C-capable microcontroller or microcomputer. Instead of getting separate I2C GPIO expanders, ADCs, PWM drivers, etc, seesaw can be configured to give a wide range of capabilities. For example, our ATSAMD09 breakout with seesaw gives you • 3 x 12-bit ADC inputs ©Adafruit Industries Page 5 of 39 • 3 x 8-bit PWM outputs • 7 x GPIO with selectable pullup or pulldown • 1 x NeoPixel output (up to 170 pixels) • 1 x EEPROM with 64 byte of NVM memory (handy for storing small access tokens or MAC addresses) • 1 x Interrupt output that can be triggered by any of the accessories • 2 x I2C address selection pins • 1 x Activity LED But you can reprogram and reconfigure the chip to have more or less of each peripheral - as long as it fits into the ATSAMD09D14's firmware! For example, there's also a UART converter but it isn't included in the default firmware. The ATSAMD09 breakout is great for development of seesaw capabilities (we use it in-house for our design work) or you can use it as-is to give your Raspberry Pi or ESP8266 more hardware support! Each breakout comes with the assembled and tested board, as well as some header strips. Please note: The boards do not come with a bootloader. If you want to do development using seesaw you'll need to pick up a J-Link  (https://adafru.it/BrS)and we recommend a SWD adapter breakout (https://adafru.it/u7d) - at this time our project is for Atmel Studio but you could probably get it working with arm gcc and a Makefile. We don't provide any support for custom builds of seesaw - we think this is cool and useful for the Maker community! ©Adafruit Industries Page 6 of 39 Pinouts ©Adafruit Industries Page 7 of 39 Power Pins: • Vin - this is the power pin. Since the ATSAMD09 uses 3.3V, we have included an on-board voltage regulator that will take 3-5VDC and safely convert it down. You can power from 3.3V to 5V • 3Vo - this is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like • GND - common ground for power and logic Logic Pins: • 23 / SCL - this is the I2C clock pin, connect to your microcontrollers I2C clock line. There is a 10K pullup on this pin to 3.3V. I2C is 'open drain' which means as long as you don't add an extra pullup you can use with 5V logic devices. • 22 / SDA - this is the I2C data pin, connect to your microcontrollers I2C data line. There is a 10K pullup on this pin to 3.3V. I2C is 'open drain' which means as long as you don't add an extra pullup you can use with 5V logic devices. • RST - this is the reset pin. Pulling this pin to ground resets the device. GPIO Pins: • Pins 9, 10, 11, 14, 15, 24, and 25 can be used as GPIO. Neopixel Pins: • Pins 9, 10, 11, 14, 15, 24, and 25 can be used as the NeoPixel output. Address Pins: • 16 / AD0 - this is the ADDR0 pin. Connect this to ground to increment the devices I2C address by 1. • 17 / AD1 - this is the ADDR1 pin. Connect this to ground to increment the devices I2C addres by 2. ADC Pins: • 2 - this pin can be configured as an ADC input. • 3 - this pin can be configured as an ADC input. ©Adafruit Industries Page 8 of 39 • 4 - this pin can be configured as an ADC input. PWM Pins: • 5 - this pin can be configured as a PWM output. • 6 - this pin can be configured as a PWM output. • 7 - this pin can be configured as a PWM output. Interrupt Pins: • 8 / IRQ - this pin gets pulled low by the seesaw to signal to your host microcontroller that an interrupt has occurred. Programming Pins: • SWD - this pin connects to SWDIO of an SWD compatible programmer to program the device over SWD. • SWC - this pin connects to SWCLK of an SWD compatible programmer to program the device over SWD. • RST - this pin connects to RESET of an SWD compatible programmer to program the device over SWD. Arduino Wiring & Test Arduino Wiring & Test You can easily wire this breakout to any microcontroller, we'll be using an Adafruit Metro M0 Express (Arduino compatible) with the Arduino IDE. But, you can use any other kind of microcontroller as well as long as it has I2C clock and I2C data lines. I2C Wiring • Connect Vin to the power supply, 3-5V is fine. • Connect GND to common power/data ground • Connect the SCL pin (23) to the I2C clock SCL pin on your Microcontroller. • Connect the SDA pin (22) to the I2C data SDA pin on your Microcontroller. ©Adafruit Industries Page 9 of 39 • Connect the positive (long lead) of an LED to pin 15 on the seesaw breakout and the other lead to GND through a 1k ohm resistor. This seesaw uses I2C address 0x49 by default. You can change this by grounding the AD0/16 and/or AD1/15 pins, but we recommend not doing that until you have it working Download Adafruit_Seesaw library To begin reading sensor data, you will need to download Adafruit_Seesaw from the Arduino library manager. Open up the Arduino library manager: Search for the Adafruit Seesaw library and install it ©Adafruit Industries Page 10 of 39 We also have a great tutorial on Arduino library installation at: http://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use (https:// adafru.it/aYM) Load Test Example Open up File->Examples->Adafruit_Seesaw->digital->blink and upload to your Arduino wired up to the seesaw breakout. If everything is wired up correctly, the led should blink on and off repeatedly. Documentation see here (https://adafru.it/BrT) for documentation of the seesaw python API. ©Adafruit Industries Page 11 of 39 CircuitPython Wiring & Test CircuitPython Wiring & Test You can easily wire this breakout to a microcontroller running CircuitPython. We will be using a Metro M0 Express. I2C Wiring • Connect Vin to the power supply, 3-5V is fine. • Connect GND to common power/data ground • Connect the SCL pin (23) to the I2C clock SCL pin on your CircuitPython board, usually marked SCL. On a Gemma M0 this would be Pad #2/ A1 • Connect the SDA pin (22) to the I2C data SDA pin on your CircuitPython board, usually marked SDA. On an Gemma M0 this would be Pad #0/A2 • Connect the positive (long lead) of an LED to pin 15 on the samd09 breakout and the other lead to GND through a 1k ohm resistor. The seesaw uses I2C address 0x49 by default. You can change this by grounding the AD0/16 and/or AD1/15 pins, but we recommend not doing that until you have it working ©Adafruit Industries Page 12 of 39 Download Adafruit_CircuitPython_Seesaw library To begin using the seesaw, you will need to download Adafruit_CircuitPython_Seesaw from our github repository. You can do that by visiting the github repo and manually downloading or, easier, just click this button to download the zip Adafruit CircuitPython Seesaw Library https://adafru.it/10bv Extract the zipped folder and rename the folder it contains to Adafruit_seesaw. drag the Adafruit_seesaw folder to the lib folder that appears on the CIRCUITPY drive. You'll also need the adafruit_busdevice driver. Our CircuitPython library may change APIs so consider this beta! Open the code.py file on the CIRCUITPY drive and copy and paste the following code: from board import * import busio from adafruit_seesaw.seesaw import Seesaw import time myI2C = busio.I2C(SCL, SDA) ss = Seesaw(myI2C) ss.pin_mode(15, ss.OUTPUT); ©Adafruit Industries Page 13 of 39 while True: ss.digital_write(15, True) time.sleep(1) ss.digital_write(15, False) time.sleep(1) # turn the LED on (True is the voltage level) # wait for a second # turn the LED off by making the voltage LOW The LED attached to pin 15 should blink on and off repeatedly. Python Docs Python Docs (https://adafru.it/C5y) Raspberry Pi Wiring & Test The Raspberry Pi also has an I2C interface that can be used to communicate with this seesaw. You can use this breakout with the CircuitPython library and Python thanks to Adafruit_Blinka, our CircuitPython-for-Python compatibility library (https://adafru.it/ BSN). Install Python Software You'll need to install the Adafruit_Blinka library that provides the CircuitPython library support in Python. This may also require enabling I2C on your platform and verifying you are running Python 3. Once that's done, from your command line run the following command: • sudo pip3 install adafruit-circuitpython-seesaw ©Adafruit Industries Page 14 of 39 If your default Python is version 3 you may need to run ' pip ' instead. Just make sure you aren't trying to use CircuitPython on Python 2.x, it isn't supported! Enable I2C We need to enable the I2C bus so we can communicate with the seesaw. sudo raspi-config select Advanced options, enable I2C, and then finish. ©Adafruit Industries Page 15 of 39 With the Pi powered off, we can wire up the sensor to the Pi Cobbler like this: • Connect Vin to the 3V or 5V power supply (either is fine) • Connect GND to the ground pin on the Cobbler • Connect SDA (22)  to SDA on the Cobbler • Connect SCL (23) to SCL on the Cobbler • Connect the positive (long lead) of an LED to pin 15 on the samd09 breakout and the other lead to GND through a 1k ohm resistor. You can also use direct wires, we happen to have a Cobbler ready. remember you can plug the cobbler into the bottom of the PiTFT to get access to all the pins! Now you should be able to verify that the sensor is wired up correctly by asking the Pi to detect what addresses it can see on the I2C bus: ©Adafruit Industries Page 16 of 39 sudo i2cdetect -y 1 It should show up under it's default address (0x49). If you don't see 49, check your wiring, did you install I2C support, etc? Run example code At long last, we are finally ready to run our example code. Open the Python REPL to begin. First we'll import the necessary libraries, initialise the I2C bus and setup the LED pin for use: import time import board import busio from adafruit_seesaw.seesaw import Seesaw i2c_bus = busio.I2C(board.SCL, board.SDA) ss = Seesaw(i2c_bus) ss.pin_mode(15, ss.OUTPUT) Now you're ready to blink the LED using digital_write : while True: ss.digital_write(15, True) time.sleep(1) ss.digital_write(15, False) time.sleep(1) ©Adafruit Industries Page 17 of 39 If everything is set up correctly, the LED attached to pin 15 on the SAMD09 breakout should blink on and off repeatedly. Press CTRL + C to stop the program running once you are satisfied with the blinking. Documentation See here (https://adafru.it/C5y) for documentation of the seesaw CircuitPython API. Full Example Code # SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries # SPDX-License-Identifier: MIT # Simple seesaw test using an LED attached to Pin 15. # # See the seesaw Learn Guide for wiring details: # https://learn.adafruit.com/adafruit-seesaw-atsamd09-breakout? view=all#circuitpython-wiring-and-test import time import board from adafruit_seesaw.seesaw import Seesaw i2c_bus = board.I2C() ss = Seesaw(i2c_bus) ss.pin_mode(15, ss.OUTPUT) while True: ss.digital_write(15, True) # turn the LED on (True is the voltage level) time.sleep(1) # wait for a second ss.digital_write(15, False) # turn the LED off by making the voltage LOW time.sleep(1) ©Adafruit Industries Page 18 of 39 Using the Seesaw Platform The sections under this heading contain more detailed information about how the Seesaw platform works. If you are using our Arduino, CircuitPython, or Python API you can skip these sections. These sections are intended for people who either want to understand and modify seesaw, or who want to make their own API for a platform that is no officially supported by Adafruit such as C/C++ on Raspberry Pi. Reading and Writing Data The SeeSaw operates as an I2C secondary device using standard I2C protocol. It uses the SDA and SCL pins to communicate with the host system. The I2C bus on the SAMD09 is 3.3V logic level, but all boards other than the SAMD09 breakout have level shifting so you can use 3 or 5V logic. Boards with Attiny chips are 3 or 5V safe so you can use either for power and logic Only 7-bit addressing is supported. I2C pullup resistors are included in our SeeSaw boards but if you are DIY'ing, be sure to add your own! 2.2K - 10K is a good range. Setting the Device Address Standard 7-bit addressing is used. The seesaw's default I2C address is initially configured in the compiled firmware (e.g for theSeeSaw breakouts we use 0x49) but other boards will have a different base address. Check the board documentation for the default base I2C address, or you can plug it in and scan the I2C bus to find it (http s://adafru.it/YEf). This address can be modified using the address select pins, there can be multiple address pins. If address select pin 0 (A0) is tied to ground on boot, the I2C address is incremented by 1. If address select pin 1 (A1) is pulled low, the I2C address is incremented by 2. If both address select pins are pulled low, the I2C address is incremented by 3. Thus you can, with the same hardware, have up to 4 devices ©Adafruit Industries Page 19 of 39 On both the SAMD09 and Attiny817 breakouts, the default A0 pin is 16, default A1 pin is 17. On boards where the chips are embedded, there may be as many as 4 address pins, they'll be labeled with jumpers The base I2C address can also be modified by writing a new address to EEPROM. See the EEPROM section for more information. I2C Transactions We recommend using 100KHz I2C, but speeds of up to 400KHz are supported. You may want to decrease the SDA/SCL pullups to 2.2K from 10K in that case. Writing Data A seesaw write command consists of the standard I2C write header (with the R/W bit set to 0), followed by 2 register bytes followed by zero or more data bytes. The first register byte is the module base register address. Each module (GPIO, ADC, DAC, etc.) has it's own unique 8 bit base identifier. The second register byte is the module function register address. This byte specifies the desired register within the module to be written. Thus we have up to 254 modules available (0x00 is reserved) and 255 functions per module - plenty to allow all sorts of different capabilities! In code, this may look like this (using the Arduino wire I2C object): void Adafruit_seesaw::write(uint8_t moduleBase, uint8_t moduleFunction, uint8_t *buf, uint8_t num) { Wire.beginTransmission((uint8_t)_i2caddr); Wire.write((uint8_t)moduleBase); //module base register address Wire.write((uint8_t)moduleFunction); //module function register address Wire.write((uint8_t *)buf, num); //data bytes Wire.endTransmission(); } The Arduino UNO Wire library implementation has a limit of 32 bytes per transaction so be aware you may not be able to read/write more than that amount. We have designed the library to work within those constraints ©Adafruit Industries Page 20 of 39 Reading Data A register read is accomplished by first sending the standard I2C write header, followed by the two register bytes corresponding to the data to be read. Allow a short delay, and then send a standard I2C read header (with the R/W bit set to 1) to read the data. The length of the required delay depends on the data that is to be read. These delays are discussed in the sections specific to each module. In code, this may look like this  (using the Arduino wire I2C object): void Adafruit_seesaw::read(uint8_t moduleBase, uint8_t moduleFunction, uint8_t *buf, uint8_t num, uint16_t delay) { Wire.beginTransmission((uint8_t)_i2caddr); Wire.write((uint8_t)moduleBase); //module base register address Wire.write((uint8_t)moduleFunction); //module function register address Wire.endTransmission(); delayMicroseconds(delay); Wire.requestFrom((uint8_t)_i2caddr, num); for(int i=0; i<num; i++){ buf[i] = Wire.read(); } } GPIO The GPIO module provides every day input and outputs. You'll get logic GPIO pins that can act as outputs or inputs. With pullups or pulldowns. When inputs, you can also create pin-change interrupts that are routed the the IRQ pin. On SAMD09-based boards the GPIO is 3V only. On ATtiny-based boards, the GPIO logic is whatever the power pin is, 3V or 5V. The module base register address for the GPIO module is 0x01.  ©Adafruit Industries Page 21 of 39  Function Registers Register Address Function Name Register Size Notes 0x02 DIRSET 32 bits Write Only 0x03 DIRCLR 32 bits Write Only 0x04 GPIO 32 bits Read/Write 0x05 SET 32 bits Write Only 0x06 CLR 32 bits Write Only 0x07 TOGGLE 32 bits Write Only 0x08 INTENSET 32 bits Write Only 0x09 INTENCLR 32 bits Write Only 0x0A INTFLAG 32 bits Read Only 0x0B PULLENSET 32 bits Write Only 0x0C PULLENCLR 32 bits Write Only ©Adafruit Industries Page 22 of 39 Writes of GPIO function registers should contain 4 data bytes (32 bits) following the initial register data bytes. Each bit in these registers represents a GPIO pin on PORTA of the seesaw device. If the corresponding pin does not exist on the SeeSaw device, then reading or writing the bit has no effect. We decided to go with this method to make GPIO toggling fast (rather than having one i2c transaction per individual pin control) but the host processor will need to do a little work to keep the pins identified. GPIO register setup on SAMD09: Bit 31 Bit 30 Bit 29 Bit 28 Bit 27 .  .  . Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 PA31 PA30 PA29 PA28 PA27 .  .  . PA04 PA03 PA02 PA01 PA00 GPIO register setup on ATTiny8x7: (this is the same as the megaTinyCore pin mapping (https://adafru.it/YEh)) • Bit 0: PA4 • Bit 1: PA5 • Bit 2: PA6 • Bit 3: PA7 • Bit 4: PB7 • Bit 5: PB6 • Bit 6: PB5 • Bit 7: PB4 • Bit 8: PB3 • Bit 9: PB2 • Bit 10: PB1 • Bit 11: PB0 • Bit 12: PC0 • Bit 13: PC1 • Bit 14: PC2 ©Adafruit Industries Page 23 of 39 • Bit 15: PC3 • Bit 16: PC4 • Bit 17: PC5 • Bit 18: PA1 • Bit 19: PA2 • Bit 20: PA3 DIRSET (0x02, 32 bits, Write Only) Writing a 1 to any bit in this register sets the direction of the corresponding pin to OUTPUT. Writing zeros to this register has no effect. DIRCLR (0x03, 32 bits, Write Only) Writing a 1 to any bit in this register sets the direction of the corresponding pin to INPUT. Writing zeros to this register has no effect. GPIO (0x04, 32 bits, Read/Write) When this register is written, all bits that are set to 0 will have their corresponding pins set LOW. All bits that are set to 1 will have their corresponding pins set HIGH. Reading this register reads all pins on of the seesaw device. On the Attiny series please wait at least 250uS between command write and data read to allow the data to be read and formatted for retrieval. Reading this register will also reset the IRQ pin if it was configured. SET (0x05, 32 bits, Write Only) Writing a 1 to any bit in this register writes the corresponding pin HIGH. ©Adafruit Industries Page 24 of 39 Writing zeros to this register has no effect. CLR (0x06, 32 bits, Write Only) Writing a 1 to any bit in this register writes the corresponding pin LOW. Writing zeros to this register has no effect. TOGGLE (0x07, 32 bits, Write Only) Writing a 1 to any bit in this register toggles the corresponding pin. Writing zeros to this register has no effect. INTENSET (0x08, 32 bits, Write Only) Writing a 1 to any bit in this register enables the interrupt on the corresponding pin. When the value on this pin changes, the corresponding bit will be set in the INTFLAG register. Writing zeros to this register has no effect. INTENCLR (0x09, 32 bits, Write Only) Writing a 1 to any bit in this register disables the interrupt on the corresponding pin. Writing zeros to this register has no effect. INTFLAG (0x0A, 32 bits, Read Only) This register hold the status of all GPIO interrupts. When an interrupt fires, the corresponding bit in this register gets set. Reading this register clears all interrupts. T his will also reset the IRQ pin if it was configured. Writing to this register has no effect. ©Adafruit Industries Page 25 of 39 PULLENSET (0x0B, 32 bits, Write Only) Writing a 1 to any bit in this register enables the internal pullup or pulldown on the corresponding pin. The pull direction (up/down) is determined by the GPIO (output) value - if the corresponding GPIO register bit is low,  its a pulldown. High, its a pullup. Writing zeros to this register has no effect. PULLENCLR (0x0C, 32 bits, Write Only) Writing a 1 to any bit in this register disables the pull up/down on the corresponding pin. Writing zeros to this register has no effect. Analog to Digital Converter The ADC provides the ability to measure analog voltages at 10-bit resolution. The SAMD09 seesaw has 4 ADC inputs, the Attiny8x7 has 11 ADC inputs. The module base register address for the ADC is 0x09 Conversions can be read by reading the corresponding CHANNEL register. When reading ADC data, there should be at least a 500 uS delay between writing the register number you would like to read from and attempting to read the data. Allow a delay of at least 1ms in between sequential ADC reads on different channels. SAMD09 ADC channels are: Channel 0 PA02 Channel 1 PA03 ©Adafruit Industries Page 26 of 39 Channel 2 PA04 Channel 3 PA05 ATtiny8x7 ADC channels are: • Channel 0: PA4 • Channel 1: PA5 • Channel 2: PA6 • Channel 3: PA7 • Channel 6: PB5 • Channel 7: PB4 • Channel 10: PB1 • Channel 11: PB0 • Channel 18: PA1 • Channel 19: PA2 • Channel 20: PA3 (These are the same as the Arduino GPIO pin names for the ADCs in megaTinyCore (h ttps://adafru.it/YEh)) Function Registers Register Address Register Name Register Size Notes 0x00 STATUS 8 bits Read Only 0x02 INTENSET 8 bits Write Only 0x03 INTENCLR 8 bits Write Only 0x04 WINMODE ©Adafruit Industries Write Only Page 27 of 39 0x05 WINTHRESH 32 bits Write Only 0x07 CHANNEL_0 16 bits Read Only 0x08 CHANNEL_1 16 bits Read Only 0x09 CHANNEL_2 16 bits Read Only 0x0A CHANNEL_3 16 bits Read Only ... ... ... ... CHANNEL_20 16-bit Read Only 0x1B Window mode or ADC interrupts is not yet supported as of the time of writing this guide. STATUS (0x00, 8bits, Read Only) This register contains status information on the ADC Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Reserved Reserved Reserved Reserved Reserved Reserved WINMON_INT ERROR ©Adafruit Industries Page 28 of 39   INTENSET (0x02, 8bits, Write Only) Writing a 1 to any bit in this register enables the corresponding interrupt. Writing zeros to this register has no effect. Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Reserved Reserved Reserved Reserved Reserved Reserved Reserved WINMON INTENCLR (0x03, 8bits, Write Only) Writing a 1 to any bit in this register enables the corresponding interrupt. Writing zeros to this register has no effect. WINMODE (0x04, 8bits, Write Only) Writing 1 to this register sets window control. WINTHRESH (0x05, 32bits, Write Only) This register sets the threshold values for window mode. Bits 31 - 16 Bits 15 - 0 High Threshold Low Threshold ©Adafruit Industries Page 29 of 39 CHANNEL_0 (0x07, 16bits, Read Only) ADC value for channel 0 CHANNEL_1 (0x08, 16bits, Read Only) ADC value for channel 1 CHANNEL_2 (0x09, 16bits, Read Only) ADC value for channel 2 CHANNEL_3 (0x0A, 16bits, Read Only) ADC value for channel 3 ... CHANNEL_20 (0x1B, 16bits, Read Only) ADC value for channel 20 Interrupts The seesaw has a configurable interrupt pin that can be triggered through various channels. Once the interrupt is triggered, it can be only be cleared when the conditions of it's source module(s) have been met (e.g. data has been read, an interrupt has been cleared by reading an INTFLAG register). See individual module sections for details on their available interrupt configurations. The hardware interrupt pin is available on PA08 (#8) ©Adafruit Industries Page 30 of 39 NeoPixel The seesaw has built in NeoPixel support for up to 170 RGB or 127 RGBW pixels. The output pin as well as the communication protocol frequency are configurable. Note: older firmware is limited to 63 pixels max. The module base register address for the NeoPixel module is 0x0E. Function Registers Register Address Register Name Register Size Notes 0x01 PIN 8 bits Write Only 0x02 SPEED 8 bits Write Only 0x03 BUF_LENGTH 16 bits Write Only 0x04 BUF 32 bytes Write Only 0x05 SHOW none Write Only PIN (0x01, 8bits, Write Only) This register sets the pin number (PORTA) that is used for the NeoPixel output. SPEED (0x02, 8bits, Write Only) The protocol speed. 0x00 = 400khz ©Adafruit Industries Page 31 of 39 0x01 = 800khz (default) BUF_LENGTH (0x03, 16bits, Write Only) the number of bytes currently used for the pixel array. This is dependent on when the pixels you are using are RGB or RGBW. BUF (0x04, 32 bytes, Write Only) The data buffer. The first 2 bytes are the start address, and the data to write follows. Data should be written in blocks of maximum size 30 bytes at a time. Bytes 0 - 1 Bytes 2 - 32 Start address Data SHOW (0x05, no args, Write Only) Sending the SHOW command will cause the output to update. There's no arguments/ data after the command EEPROM The EEPROM module provides persistent storage of data across reboots. On the SAMD09, there are 64 bytes of emulated EEPROM available for use. Byte 63 (0x3F) can be written to change the devices default I2C address. On the ATtiny817, there are 128 bytes of actual EEPROM available for use. Byte 127 (0x 7F) can be written to change the device's default I2C address. The module base register address for the EEPROM module is 0x0D  The SAMD09 does not have true EEPROM, but flash memory on the seesaw that performs the same function. Performing a chip erase will erase all data stored in ©Adafruit Industries Page 32 of 39 the emulated EEPROM. Also, be aware that the emulated EEPROM has a limited write/erase cycle lifespan. Care should be taken to not write/erase too many times or you will get inconsistant results and possibly damage the FLASH! The FLASH is rated for 100,000 cycles Function Registers SAMD09 Register Address Function Name Register Size Notes 0x00 - 0x3E General Purpose EEPROM 8 bits each Read/Write 0x3F I2C Address 8 bits Read/Write Register Address Function Name Register Size Notes 0x00 - 0x7E General purpose EEPROM 8 bits each Read/write 0x7F I2C Address 8 bits Read/write ATtiny817 PWM The PWM module provides up to 4 8-bit PWM outputs. The module base register address for the PWM module is 0x08.  PWM outputs are available on pins PA04, PA05, PA06, and PA07. ©Adafruit Industries Page 33 of 39 Function Registers Register Address Register Name Register Size Notes 0x01 PWM_VAL 16 bits Write Only PWM_VAL (0x01, 16bits, Write Only)   Byte 0 Byte 1 PWM Number PWM Value The first byte written should be the PWM number you would like to write to. The second byte should be the pwm value. PWM Number Output Pin 0 PA04 1 PA05 2 PA06 3 PA07 ©Adafruit Industries Page 34 of 39 UART Note that the default firmware on the SAMD09 breakout does not include UART support. When the UART module is configured, the seesaw can act as an I2C UART bridge. UART Pins are: RX: PA11 TX: PA10 The module base register address for the UART is 0x02. The I2C UART bridge is still in beta at the time of writing this guide. Detailed specs are not yet available. Function Registers Register Address Register Name Regsiter Size Notes 0x00 STATUS 8 bits Read Only 0x02 INTEN 8 bits Read/Write 0x03 INTENCLR 8 bits Write Only 0x04 BAUD 32 bits Read/Write 0x05 DATA 32 bytes Read/Write ©Adafruit Industries Page 35 of 39 Status (0x00, 8bits, Read Only)   bits 7-2 bit 1 bit 0 Reserved DATA_RDY ERROR The ERROR bit is set when the UART encounters an error. The DATA_RDY bit is set when there is data available in the RX buffer. This bit gets cleared when the data is read. INTEN (0x2, 8bits, Read/Write)   bits 7-1 bit 0 Reserved DATA_RDY If the DATA_RDY bit is set, the interrupt will fire when there is data in the RX buffer. Writing zeros to this register has no effect. INTENCLR (0x03, 8bits, Write Only) same bits as INTEN. Writing 1 to any bit in this register disabled the corresponding interrupt. Writing zeros to this register has no effect. ©Adafruit Industries Page 36 of 39 BAUD (0x04, 32bits, Read/Write) Writing to this register sets the BAUD rate. Default 9600 DATA (0x05, 32bytes, Read/Write ) Writing to the DATA register puts the data into the TX buffer to be output on the TX pin. Reading from the DATA register reads the data from the RX buffer. When this register is read, the DATA_RDY bit is cleared. Downloads Documents • Seesaw Arduino Driver (https://adafru.it/BrV) • Seesaw CircuitPython Driver (https://adafru.it/BrW) • Fritzing object in the Adafruit Fritzing library (https://adafru.it/aP3) • SAMD09 breakout PCB files (EAGLE format) (https://adafru.it/BrX) • SAMD09 datasheet (https://adafru.it/BrY) Schematic click to enlarge ©Adafruit Industries Page 37 of 39 Dimensions in inches. Click to enlarge ©Adafruit Industries Page 38 of 39 Documentation • Python API Documentation (https://adafru.it/BrT) • Arduino API Documentation (https://adafru.it/CBQ) ©Adafruit Industries Page 39 of 39