Based on kernel version 2.6.31. Page generated on 2009-09-16 22:26 EST.
1 Kernel driver pca9539 2 ===================== 3 4 NOTE: this driver is deprecated and will be dropped soon, use 5 drivers/gpio/pca9539.c instead. 6 7 Supported chips: 8 * Philips PCA9539 9 Prefix: 'pca9539' 10 Addresses scanned: none 11 Datasheet: 12 http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf 13 14 Author: Ben Gardner <bgardner[AT]wabtec[DOT]com> 15 16 17 Description 18 ----------- 19 20 The Philips PCA9539 is a 16 bit low power I/O device. 21 All 16 lines can be individually configured as an input or output. 22 The input sense can also be inverted. 23 The 16 lines are split between two bytes. 24 25 26 Detection 27 --------- 28 29 The PCA9539 is difficult to detect and not commonly found in PC machines, 30 so you have to pass the I2C bus and address of the installed PCA9539 31 devices explicitly to the driver at load time via the force=... parameter. 32 33 34 Sysfs entries 35 ------------- 36 37 Each is a byte that maps to the 8 I/O bits. 38 A '0' suffix is for bits 0-7, while '1' is for bits 8-15. 39 40 input[01] - read the current value 41 output[01] - sets the output value 42 direction[01] - direction of each bit: 1=input, 0=output 43 invert[01] - toggle the input bit sense 44 45 input reads the actual state of the line and is always available. 46 The direction defaults to input for all channels. 47 48 49 General Remarks 50 --------------- 51 52 Note that each output, direction, and invert entry controls 8 lines. 53 You should use the read, modify, write sequence. 54 For example. to set output bit 0 of 1. 55 val=$(cat output0) 56 val=$(( $val | 1 )) 57 echo $val > output0