Intel Edison Compute Module (IoT) Spécifications télécharger pdf (Page 12)

Shield pin configuration

2.6 Pin direction and pullup control

For most shield pins on the Intel® Edison kit for Arduino*, there is a buffer/level-shifter which needs to be

configured for input or output direction, and an external 47 kohm pullup/pulldown resistor, which may be

optionally enabled. Both are driven by dedicated GPIO outputs, listed in Table 7. When configuring a shield pin as

an output, we advise configuring the buffer for output before setting the SoC GPIO pin direction to output. To

disconnect the external pullup/pulldown resistors, it is necessary to configure as high-impedance inputs the GPIOs

that drive them.

Note also that the GPIO signals from the PCAL9555A GPIO expanders have internal 100 kohm pullup resistors,

which are connected to the GPIO pins by default. These need to be disabled in many cases, by configuring those

pins as high-impedance inputs.

Table 7

Pin direction and pullup control

Shield

Output enable GPIO (high = output)

Pullup enable GPIO

Linux

Power-on default

Linux

Power-on default

IO0

U34_ IO0.0

248

Pulled-down input

U39_IO0.0

216

Pulled up input

IO1

U34_ IO0.1

249

Pulled-down input

U39_IO0.0

217

Pulled up input

IO2

U34_ IO0.2

250

Pulled-down input

U39_IO0.0

218

Pulled up input

IO3

U34_ IO0.3

251

Pulled-down input

U39_IO0.0

219

Pulled up input

IO4

U34_ IO0.4

252

Pulled-down input

U39_IO0.0

220

Pulled up input

IO5

U34_ IO0.5

253

Pulled-down input

U39_IO0.0

221

Pulled up input

IO6

U34_ IO0.6

254

Pulled-down input

U39_IO0.0

222

Pulled up input

IO7

U34_ IO0.7

255

Pulled-down input

U39_IO0.7

223

Pulled up input

IO8

U34_ IO1.0

256

Pulled-down input

U39_IO0.7

224

Pulled up input

IO9

U34_ IO1.1

257

Pulled-down input

U39_IO0.7

225

Pulled up input

IO10

U34_ IO1.2

258

Pulled-down input

U39_IO0.7

226

Pulled up input

IO11

U34_ IO1.3

259

Pulled-down input

U39_IO0.7

227

Pulled up input

IO12

U34_ IO1.4

260

Pulled-down input

U39_IO0.7

228

Pulled up input

IO13

U34_ IO1.5

261

Pulled-down input

U39_IO0.7

229

Pulled up input

IO14

U16_ IO0.0

232

Pulled-down input

U17_ IO1.0

208

Pulled up input

IO15

U16_ IO0.1

233

Pulled-down input

U17_ IO1.1

209

Pulled up input

IO16

U16_ IO0.2

234

Pulled-down input

U17_ IO1.2

210

Pulled up input

IO17

U16_ IO0.3

235

Pulled-down input

U17_ IO1.3

211

Pulled up input

IO18

U16_ IO0.4

236

Pulled-down input

U17_ IO1.4

212

Pulled up input

IO19

U16_ IO0.5

237

Pulled-down input

U17_ IO1.5

213

Pulled up input

1 These pins are externally pulled down inputs at power-on. This effectively selects input direction for level shifters.

2 These pins are internally pulled up inputs at power-on. This effectively enables pullups (as 100 kohm + 47 kohm in series).

Intel® Edison Kit for Arduino*

Hardware Guide December 2014

12 Document Number: 331191-004

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