After rebuilding the kernel, the qdac program worked just fine. It adds significantly to the boot time. The TDO pin shown in the photo is pin A typical value to use would be 4. The JTAG connector page has a photo of the hirose connector. Background I2c is a 2-wire serial 8 bit communications protocol from the old days.

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Background I2c is a 2-wire serial 8 bit communications protocol from the old days.

It includes a schematic for the voltage level conversion of the I2C lines that’s required. The FreeBSD driver supports 3 different speeds: Some cpu’s have the I2c hardware shift registers built in.

Category:How to – i2c

It has LW33 stamped on it. Jumpnow Technologies home code consulting contact.

All of the current daughter cards except the robostixneed to have pullup resistors added, which pullup the SDA and SCL lines to 3.

The bus accessible from most of the 40 pin expansion board headers is i2c These are all 3. If you use a robostix, the 3.

The default gumstix kernels set the i2c-3 bus speed to kHz. Then you have to reset the bus using the i2c 8 utility u2c it to take effect. A typical value to use would be 4.


An example can be found in omapx. This can be changed to kHz with a kernel i2d line parameter in u-boot. That kHz is most likely a mistake. On the back of the waysmall board, amongst the set of 20 pads, the pad closest to the edge of the board ii2c the power connector is the SDA signal, and the one next to it also by the edge of the board is the SCL signal.

The JTAG connector page has a photo of the hirose connector. The change does require a kernel gimstix. The device address is the first byte sent in any communication.

Make sure the value has double-quotes around it. The via to the left under the T is pin 21, the one under the O is pin 20, and the one under the D is You must set the slave address with an ioctl call prior to communicating with a slave device.

These are both 5v signals and have pullup resistors. Literature How to – i2c.

I2C Gumstix read()/write()

The pin below the 3 in LW33 is the 3. A good explanation can be found here. Navigation Main page Recent changes Random page Help. Not unexpected given the unusual clock frequency. Here’s a C example minus any error checking.


Gumstix I2C-Problem: “ioctl failed: Remote I/O error ()”

It is mainly used to communicate between on-board components when the design does not allow for a data and address bus. Personal tools Log in. I already had a Duovero connected to an MCP eval board through a level shifter. I learned that from this interesting article by Vadim Zaigrin about using ktrace 1 to debug the I2C bus on a Raspberry Pi. Because of patents that have since expired, other companies had to use slightly different ways to do the same thing so a very similar serial communications method called SPI uses 4 wires and another called TWI uses the same 2 wires.

I put an oscope on the SCL line and found the clock running at kHz.