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29 * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
33 * \brief PCF8574 i2c port expander driver.
35 * This driver controls the PCF8574.
36 * The PCF8574 is an 8bit i2c port expander.
37 * You can read/write 8 pins through an i2c bus.
38 * The pins are quasi-bidirectionals, this mean that
39 * without the need of a direction register you can use
40 * each pin as input or output, see datasheet on how this
44 * \author Francesco Sacchi <batt@develer.com>
48 #include <cfg/module.h>
52 * Read PCF8574 \a pcf bit status.
53 * \return the pins status or EOF on errors.
55 int pcf8574_get(Pcf8574 *pcf)
57 if (!i2c_start_r(PCF8574ID | ((pcf->addr << 1) & 0xF7)))
60 int data = i2c_get(false);
66 * Write to PCF8574 \a pcf port \a data.
67 * \return true if ok, false on errors.
69 bool pcf8574_put(Pcf8574 *pcf, uint8_t data)
71 bool res = i2c_start_w(PCF8574ID | ((pcf->addr << 1) & 0xF7)) && i2c_put(data);
77 * Init a PCF8574 on the bus with addr \a addr.
78 * \return true if device is found, false otherwise.
80 bool pcf8574_init(Pcf8574 *pcf, pcf8574_addr addr)
84 return pcf8574_get(pcf) != EOF;