Hardware/CubeSat Gumstix/Test/ADC
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= Gumstix = | = Gumstix = | ||
− | Log-in to the Gumstix via the USB serial console | + | Log-in to the Gumstix via the USB serial console. |
+ | Make sure you belong to the group <code>dialout</code>. | ||
List the possible serial ports: | List the possible serial ports: | ||
ls -l /dev/tty* | ls -l /dev/tty* | ||
+ | |||
+ | With [https://www.yoctoproject.org/organization/gumstix Yocto Linux], the device is <code>ttyO0</code> | ||
[[Category:Hardware]] | [[Category:Hardware]] | ||
[[Category:Cubesat]] | [[Category:Cubesat]] | ||
[[Category:Gumstix]] | [[Category:Gumstix]] |
Revision as of 16:53, 26 October 2015
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The ADC controller design reads the 8 ADC channels together with the temperature value and sends the values to the serial port.
The UART baud rate is 115˙200. The ADC sampling rate is 100 Hz, due to the slow UART text transmission. The ADC's SPI connection runs at 12.5 MHz (100 MHz / 4 / 2).
SPI
The ADC's SPI interface is mirrored on the peripheral 2 connector:
- CS_n pin 5
- SCLK pin 6
- MOSI pin 7
- MISO pin 8
- RST_N pin 9
- BUSY pin 10
Serial port
The serial data out is provided on the serial port to the Gumstix. It is mirrored on the peripheral 2 connector:
- GND pin 2
- TxD pin 3 (not used)
- RxD pin 4
The FTDI serial-USB adapter uses:
- GND: black
- TxD: orange
- RxD: yellow
Measurements
With a 5 V voltage reference, the reading should be:
- FFFh for the 5 V on channel 0
- A8Fh for the 3.3 V on channels 1 to 3
- 800h for the 2.5 V on channel 1
- 5C2h for the 1.8 V on channel 2
- 3D7h for the 1.2 V on channel 4
Gumstix
Log-in to the Gumstix via the USB serial console.
Make sure you belong to the group dialout
.
List the possible serial ports:
ls -l /dev/tty*
With Yocto Linux, the device is ttyO0