Difference between revisions of "MCP4912"
From ArmadeusWiki
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=== set values === | === set values === | ||
<pre class="apf"> | <pre class="apf"> | ||
| − | # cd /sys/bus/spi/devices/spi0.1/ | + | # cd /sys/bus/spi/devices/spi0.1/device0 |
# ls | # ls | ||
dac_power_mode_0 out0_raw power uevent | dac_power_mode_0 out0_raw power uevent | ||
Revision as of 15:01, 26 April 2011
Contents
Description
This 2 channels 10bits SPI DAC (Digital to Analog Converter) is mounted in standard on the APF51Dev development boards.
Connections
On your Devlight/DevFull there are 3 signals to use the Max5821:
- DAC_OUTA: corresponds to OUTA (pin 1 of J5 on the APF51Dev). It's the first output.
- DAC_OUTB: corresponds to OUTB (pin 10 of J5 on the APF51Dev). It's the 2nd output.
The default output voltage range is 0->2.5V on the APF51Dev because the reference output of the AS1531 is used as reference for the mcp4912
Driver
The driver is included in ARMadeus distribution, then to use it, select it :
[ ] $ make linux26-menuconfig
Device Drivers --->
<*> Staging drivers --->
<*> Industrial I/O support --->
<M> Microchip MCP4902, MCP4912, MCP4922 driver
Then compile the distribution :
[ ] $ make linux26;make
Use it
modprobe
To use the DAC first load module:
# modprobe mcp49x2
set values
# cd /sys/bus/spi/devices/spi0.1/device0 # ls dac_power_mode_0 out0_raw power uevent dac_power_mode_1 out1_raw subsystem
To set the dac value :
# cat in5_input 887
