GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
TI_ADC(4) FreeBSD Kernel Interfaces Manual TI_ADC(4)

ti_adc
TI AM3XXX analog to digital converter driver

device ti_adc

The ti_adc driver provides access to the AIN (analog inputs) on am3xxx SoCs.

It provides raw readings of the converted values for each analog inputs.

The access to ti_adc data is made via the sysctl(8) interface:

dev.ti_adc.0.%desc: TI ADC controller
dev.ti_adc.0.%driver: ti_adc
dev.ti_adc.0.%pnpinfo: name=adc@44E0D000 compat=ti,adc
dev.ti_adc.0.%parent: simplebus0
dev.ti_adc.0.clockdiv: 2400
dev.ti_adc.0.ain.0.enable: 0
dev.ti_adc.0.ain.0.open_delay: 0
dev.ti_adc.0.ain.0.samples_avg: 0
dev.ti_adc.0.ain.0.input: 0
dev.ti_adc.0.ain.1.enable: 0
dev.ti_adc.0.ain.1.open_delay: 0
dev.ti_adc.0.ain.1.samples_avg: 0
dev.ti_adc.0.ain.1.input: 0
dev.ti_adc.0.ain.2.enable: 0
dev.ti_adc.0.ain.2.open_delay: 0
dev.ti_adc.0.ain.2.samples_avg: 0
dev.ti_adc.0.ain.2.input: 0
dev.ti_adc.0.ain.3.enable: 0
dev.ti_adc.0.ain.3.open_delay: 0
dev.ti_adc.0.ain.3.samples_avg: 0
dev.ti_adc.0.ain.3.input: 0
dev.ti_adc.0.ain.4.enable: 0
dev.ti_adc.0.ain.4.open_delay: 0
dev.ti_adc.0.ain.4.samples_avg: 0
dev.ti_adc.0.ain.4.input: 0
dev.ti_adc.0.ain.5.enable: 0
dev.ti_adc.0.ain.5.open_delay: 0
dev.ti_adc.0.ain.5.samples_avg: 0
dev.ti_adc.0.ain.5.input: 0
dev.ti_adc.0.ain.6.enable: 1
dev.ti_adc.0.ain.6.open_delay: 0
dev.ti_adc.0.ain.6.samples_avg: 4
dev.ti_adc.0.ain.6.input: 2308
dev.ti_adc.0.ain.7.enable: 1
dev.ti_adc.0.ain.7.open_delay: 0
dev.ti_adc.0.ain.7.samples_avg: 0
dev.ti_adc.0.ain.7.input: 3812

On Beaglebone-black the analog input 7 is connected to the 3V3B rail through a voltage divisor (2:1). The 3V3B voltage rail comes from the TL5209 LDO regulator which is limited to 500mA maximum.

Global settings:

dev.ti_adc.0.clockdiv
Sets the ADC clock prescaler. The minimum value is 10 and the maximum is 65535. The ADC clock is based on CLK_M_OSC (24Mhz) / clockdiv. This gives a maximum of ~2.4Mhz for the ADC clock and ~10Khz for the default setting (clockdiv = 2400).

Settings per input:

dev.ti_adc.0.ain.%d.enable
Enable the conversion for the input. Each input should be individually enabled before it can be used. When all the inputs are disabled, the ADC is turned off.
dev.ti_adc.0.ain.%d.open_delay
Sets the number of ADC clock cycles to wait after applying the input configuration and before start the ADC conversion.
dev.ti_adc.0.ain.%d.samples_avg
Sets the number of samples average used on each input, it can be set to 0 (no samples average), 2, 4, 8, or 16.
dev.ti_adc.0.ain.%d.input
Is the converted raw value of the voltage applied on the analog input. It is made of a 12 bit value (0 ~ 4095).

sysctl(8)

The ti_adc driver first appeared in FreeBSD 10.1.

The driver and this manual page was written by Luiz Otavio O Souza <loos@FreeBSD.org>.
June 1, 2014 FreeBSD 13.1-RELEASE

Search for    or go to Top of page |  Section 4 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.