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Recommended method for attaching to serial peripheral (RFID reader)?

Michael_M_Intel
Employee
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What is the recommended method for attaching Galileo, with IoT Yocto, to a serial device? I think my choices are the audio jack RS232 or a USB2serial cable attached to the USB host port. The latter requiring a driver.

Thanks,
Mike

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Stewart_C_Intel
Employee
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Galileo has two physical serial ports, one is connected to the 3 pin 3.5mm Jack, (serial0) and the other is connected to the TX/RX pins on the Arduino style header. So I would recommend the Arduino header, as this is 5V and the RFID reader is likely the same voltage levels. (my one is for example). The 3.5,mm jack is a true RS-232 port, ie with +/- signalling.

I think they are addressed as serial0 and serial1  in the Arduino IDE but I don't have an example handy to check.

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Michael_M_Intel
Employee
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I need RS232, so I'd have to go find an RS232 shield. I'll try the audio jack.

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Brendan_L_Intel
Employee
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Michael M (Intel) wrote:

I need RS232, so I'd have to go find an RS232 shield. I'll try the audio jack.

There are Rx & Tx pins on the Galileo which connects to a UART (pin1&2). Note this is a TTL not pure rs232 interface. Although depending on your device connecting this may actually be better for you.

Using the serial rs232 may be a little dodgy since you'll get some garbage input to your device on boot etc...

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Matthias_H_Intel
Employee
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Brendan Le Foll (Intel) wrote:

Using the serial rs232 may be a little dodgy since you'll get some garbage input to your device on boot etc...

which you obviously could disable by removing the serial output in grub. Granted, it's slightly harder for the SPI output where you would need to reflash ...

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Brendan_L_Intel
Employee
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matthias-hahn (Intel) wrote:
which you obviously could disable by removing the serial output in grub. Granted, it's slightly harder for the SPI output where you would need to reflash ...

Yeah sure, if you recompile your own EDKII firmware, and then change the kernel parameters, you can stop the output on the rs232 port. But I wouldn't advise doing that without a dediprog handy!

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Michael_M_Intel
Employee
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I ordered an RS232 shield--sounds like that's the way to go.

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Matthias_H_Intel
Employee
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Brendan Le Foll (Intel) wrote:

Quote:

matthias-hahn (Intel) wrote:which you obviously could disable by removing the serial output in grub. Granted, it's slightly harder for the SPI output where you would need to reflash ...

Yeah sure, if you recompile your own EDKII firmware, and then change the kernel parameters, you can stop the output on the rs232 port. But I wouldn't advise doing that without a dediprog handy!

As far as I understand there is also a recover from SPI recovery file on USB (see document 330237-001US https://communities.intel.com/servlet/JiveServlet/previewBody/22475-102-3-26019/Galileo_BoardUserGuide_330237_001.pdf ch 2.5.4 "Force recovery"). Hence even w/o Dediprog you should be able to recover.

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Brendan_L_Intel
Employee
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matthias-hahn (Intel) wrote:
As far as I understand there is also a recover from SPI recovery file on USB (see document 330237-001US https://communities.intel.com/servlet/JiveServlet/previewBody/22475-102-3-26019/Galileo_BoardUserGuide_330237_001.pdf ch 2.5.4 "Force recovery"). Hence even w/o Dediprog you should be able to recover.

Looks really cool, thanks for pointing that out!

Also instead of an rs232 shield, I'd personally go for a mPCIe card that does rs232 like this (obviously all depends on your use case!): http://linitx.com/product/jetway-3-x-rs232-1-x-rs232422485-mini-pci-express-card/13532

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