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Diffstat (limited to 'Documentation/i2c')
| -rw-r--r-- | Documentation/i2c/chips/pcf8591 | 90 |
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diff --git a/Documentation/i2c/chips/pcf8591 b/Documentation/i2c/chips/pcf8591 deleted file mode 100644 index 5628fcf..0000000 --- a/Documentation/i2c/chips/pcf8591 +++ /dev/null @@ -1,90 +0,0 @@ -Kernel driver pcf8591 -===================== - -Supported chips: - * Philips PCF8591 - Prefix: 'pcf8591' - Addresses scanned: I2C 0x48 - 0x4f - Datasheet: Publicly available at the Philips Semiconductor website - http://www.semiconductors.philips.com/pip/PCF8591P.html - -Authors: - Aurelien Jarno <aurelien@aurel32.net> - valuable contributions by Jan M. Sendler <sendler@sendler.de>, - Jean Delvare <khali@linux-fr.org> - - -Description ------------ -The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one -analog output) for the I2C bus produced by Philips Semiconductors. It -is designed to provide a byte I2C interface to up to 4 separate devices. - -The PCF8591 has 4 analog inputs programmable as single-ended or -differential inputs : -- mode 0 : four single ended inputs - Pins AIN0 to AIN3 are single ended inputs for channels 0 to 3 - -- mode 1 : three differential inputs - Pins AIN3 is the common negative differential input - Pins AIN0 to AIN2 are positive differential inputs for channels 0 to 2 - -- mode 2 : single ended and differential mixed - Pins AIN0 and AIN1 are single ended inputs for channels 0 and 1 - Pins AIN2 is the positive differential input for channel 3 - Pins AIN3 is the negative differential input for channel 3 - -- mode 3 : two differential inputs - Pins AIN0 is the positive differential input for channel 0 - Pins AIN1 is the negative differential input for channel 0 - Pins AIN2 is the positive differential input for channel 1 - Pins AIN3 is the negative differential input for channel 1 - -See the datasheet for details. - -Module parameters ------------------ - -* input_mode int - - Analog input mode: - 0 = four single ended inputs - 1 = three differential inputs - 2 = single ended and differential mixed - 3 = two differential inputs - - -Accessing PCF8591 via /sys interface -------------------------------------- - -! Be careful ! -The PCF8591 is plainly impossible to detect ! Stupid chip. -So every chip with address in the interval [48..4f] is -detected as PCF8591. If you have other chips in this address -range, the workaround is to load this module after the one -for your others chips. - -On detection (i.e. insmod, modprobe et al.), directories are being -created for each detected PCF8591: - -/sys/bus/devices/<0>-<1>/ -where <0> is the bus the chip was detected on (e. g. i2c-0) -and <1> the chip address ([48..4f]) - -Inside these directories, there are such files: -in0, in1, in2, in3, out0_enable, out0_output, name - -Name contains chip name. - -The in0, in1, in2 and in3 files are RO. Reading gives the value of the -corresponding channel. Depending on the current analog inputs configuration, -files in2 and/or in3 do not exist. Values range are from 0 to 255 for single -ended inputs and -128 to +127 for differential inputs (8-bit ADC). - -The out0_enable file is RW. Reading gives "1" for analog output enabled and -"0" for analog output disabled. Writing accepts "0" and "1" accordingly. - -The out0_output file is RW. Writing a number between 0 and 255 (8-bit DAC), send -the value to the digital-to-analog converter. Note that a voltage will -only appears on AOUT pin if aout0_enable equals 1. Reading returns the last -value written. |
