include/i2c.h File Reference

#include "fx2types.h"

Go to the source code of this file.

Functions
BOOL	i2c_write (BYTE addr, WORD len1, BYTE *addr_buf, WORD len2, BYTE *data_buf)
	write data to i2c bus.
BOOL	i2c_read (BYTE addr, WORD len, BYTE *buf)
	read data on the i2c bus.
BOOL	eeprom_read (BYTE prom_addr, WORD addr, WORD len, BYTE *buf)
	read data from an attached eeprom.
BOOL	eeprom_write (BYTE prom_addr, WORD addr, WORD len, BYTE *buf)
	write data to the eeprom
Variables
volatile __xdata BOOL	cancel_i2c_trans

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Detailed Description

Utilities for reading and writing to i2c devices and as eeproms.

Definition in file i2c.h.

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Function Documentation

BOOL eeprom_read	(	BYTE	prom_addr,
		WORD	addr,
		WORD	len,
		BYTE *	buf
	)

read data from an attached eeprom.

Writes the address of the data to read then reads len bytes into buf. This function checks the I2CS register to determine if a one or two byte address eepom was detected on the i2c bus. Reading from proms at non-standard addresses my require using the i2c_read/write commands explicitly.

Parameters:

prom_addr	eeprom i2c address
addr	address of bytes to start reading
len	number of bytes to read
buf	data buffer

BOOL eeprom_write	(	BYTE	prom_addr,
		WORD	addr,
		WORD	len,
		BYTE *	buf
	)

write data to the eeprom

This function checks the I2CS register to determin if a one or two two byte eeprom is detected. If the prom is not detected at boot time or is connected to alternate addresses, the i2c_read/write commands should be used explicitly insread of using this function.

For each byte in buf, the address is written and then the data byte. Many proms support writing multiple bytes at the same time. For these, it is also better to use i2c_read/write explicitly. This function is rather slow but is effective.

Parameters:

prom_addr	eeprom i2c address
addr	address of bytes to start writing
len	number of bytes to write
buf	data buffer

BOOL i2c_read	(	BYTE	addr,
		WORD	len,
		BYTE *	buf
	)

read data on the i2c bus.

Parameters:

addr	i2c address
len	number of bytes to read
buf	buffer to store data

BOOL i2c_write	(	BYTE	addr,
		WORD	len1,
		BYTE *	addr_buf,
		WORD	len2,
		BYTE *	data_buf
	)

write data to i2c bus.

Writes data from addr buffer 1st, then data buffer. Either buffer can be NULL (as long as you set lenN to 0).

Two buffers allows writing data all in one i2c write command without having to write a hardware address and a data byte with each i2c transaction.

Parameters:

addr	i2c address
len1	length of addr data
addr_buf	addr data
len2	length of data
data_buf	data bytes

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Variable Documentation

volatile __xdata BOOL cancel_i2c_trans

i2c_write and i2c_read set this to FALSE at the beginning of a transaction. If for some reason, the read/write is taking too long or not returning, firmware can set this to TRUE to cause the routine to abort. (Usually done via an interrupt).