USBIO24 ELEXOL, USBIO24 Datasheet - Page 8

• Manufacturer Part Number: USBIO24
• Description: DIGITAL I/O MODULE, USB TO 24 I/O
• Manufacturer: ELEXOL
• Type: USB I/O Moduler

Specifications of USBIO24

• Development Tool Type: Digital I/O Module
• Tool / Board Application: Digital Signal Transfer
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

USB I/O 24 R Datasheet
4. To read the value returned from the device you will have to send the SPI device null characters to
keep the SPI clock going. For example if you are expecting a certain number of bytes in return to a
command which was sent, you send "S" + null character for the number of bytes you wish to read.
In the example image, this can be seen in the last two bytes which are sent (implemented with don't
cares) and on the input pin you will have the valid data from the device.
Note: you may have to send out leading zero's and don't cares depending on device you are
communicating with. e.g. seven leading zero's then a start bit as per the image below.
Example image for SPI communications with the MCP3004/3008 using 8 bit segments taken from
the MCP3004./3008 datasheet. (http://www.microchip.com)
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