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en:u3_io_shield [2015/06/19 16:36] odroid [I2C IO expansion block] |
en:u3_io_shield [2015/07/29 10:35] (current) odroid [I2C IO expansion block] |
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| + | ====== Introduction U3 I/O shield on ubuntu ====== | ||
| + | {{http://dn.odroid.com/homebackup/U3IOShieldR03AS.jpg?300|}} | ||
| + | The ODROID-U3 I/O Shield board can be plugged on the neat of ODROID-U3 via tiny 8 pin and 4 pin IO connector.\\ | ||
| + | The shape and dimension are exactly same as ODROID-U3. It comes with 12pcs of PCB spacers for easier and solid stacking assembly.\\ | ||
| + | The IO shield has 3 blocks. | ||
| + | * I2C IO expansion block | ||
| + | * Arduino Compatible block | ||
| + | * SPI Interface block(ODROID-U3+ and I/O shield Rev_0.3 or later) | ||
| + | |||
| + | [[http://www.hardkernel.com/main/products/prdt_info.php?g_code=G138760240354|Where to buy]] | ||
| + | ===== I2C IO expansion block ===== | ||
| + | |||
| + | TI's TCA6416A I2C to Parallel Port Expander is used in this block.\\ | ||
| + | The major benefit of this device is its wide VCC range.\\ | ||
| + | It can operate from 1.65 V to 5.5 V on the P-port side and on the SDA/SCL side separately.\\ | ||
| + | It allows bidirectional voltage-level translation GPIO Expansion between 1.8V SCL/SDA(VCCI) and 5Volt Port(VCCP).\\ | ||
| + | |||
| + | == Access GPIO from linux user space. == | ||
| + | Standard Linux kernel have inside a special interface allow to access to GPIO pins. | ||
| + | |||
| + | 1. Need to super-user permition | ||
| + | <code> | ||
| + | sudo su | ||
| + | [sudo] password for odroid : odroid | ||
| + | </code> | ||
| + | |||
| + | 2. Load the kernel modules | ||
| + | <code> | ||
| + | modprobe i2c-gpio-custom bus0=4,200,199 | ||
| + | modprobe gpio-pca953x | ||
| + | </code> | ||
| + | |||
| + | 3. Set the I2C address of the module | ||
| + | <code> | ||
| + | echo tca6416 0x20 > /sys/devices/platform/i2c-gpio.4/i2c-4/new_device | ||
| + | </code> | ||
| + | |||
| + | 4. Enable GPIO's on the board.\\ | ||
| + | **If Kernel version is higher than 3.8.13.30 gpio_n = 341 ~ 356**\\ | ||
| + | else Kernel version is older than 3.8.13.30 gpio_n = 289 ~ 304\\ | ||
| + | |||
| + | <code> | ||
| + | echo NUM > /sys/class/gpio/export | ||
| + | cd /sys/class/gpio/gpioNUM | ||
| + | echo out > direction | ||
| + | echo 1 > value | ||
| + | echo 0 > value | ||
| + | </code> | ||
| + | |||
| + | ===== Arduino Compatible block ===== | ||
| + | Atmel’s ATmega328P is used as a slave CPU to expand the IO port. \\ | ||
| + | You can use the Arduino IDE on ODROID-U3 to build & upload your sketches to this Arduino-compatible block, \\ | ||
| + | without additional/external cable connections.\\ | ||
| + | Like the Arduino Uno, it has 14 digital input/output pins (of which 6 can be used as PWM outputs), \\ | ||
| + | 6 analog inputs which provides 10 bits of resolution. They operate at 5 volts range.\\ | ||
| + | |||
| + | |||
| + | ===== SPI Interface block(ODROID-U3+ and I/O shield Rev_0.3 or later) ===== | ||
