Echelon I/O Model Reference for Smart Transceivers and Neuron Chips - Manual (Page 59)

I/O Model Reference 49
the 1-Wire bus. The last_discrepancy variable is used internally and should not
be modified.
To start a new search:
1. Call touch_first( )
2. As long as the search_done flag is not set, call touch_next( ) as many
times as are required.
For a Series 3100 device, each call to touch_first( ) or touch_next( ) takes 41 ms to
execute at 10 MHz (63 ms at 5 MHz) when a device is being read. For a Series
5000 device, each call to touch_first( ) or touch_next( ) takes 14 ms to execute at
80 MHz (29 ms at 10 MHz) when a device is being read.
unsigned crc8(unsigned crc , unsigned new-data );
This function performs the Dallas 1-Wire 8-bit cyclic redundancy check (CRC)
function on the crc and new-data arguments, and returns the new 8-bit CRC
value. You must include <stdlib.h> in your program to use this function.
unsigned long crc16(unsigned long crc , unsigned new-data );
This function performs the Dallas 1-Wire 16-bit CRC function on the crc and
new-data arguments, and returns the new 16-bit CRC value. You must include
<stdlib.h> in your program to use this function.
Certain 1-Wire devices, such as the Maxim Integrated Products DS18S20 High-
Precision 1-Wire Digital Thermometer, require that the 1-Wire bus be actively
held high during certain operations. These devices require more current than a
typical external pull-up resistor can provide for device operations. The following
functions (named touch_ xxx _spu) drive the Neuron Chip or Smart Transceiver
output to an active high state when the pin is idle. These functions require
system firmware version 18 or later.
int touch_reset_spu(unsigned pinmask );
The touch_reset_spu( ) function asserts the reset pulse, just as the touch_reset( )
function does. The
pinmask defines which pins are driven high when idle.
void touch_byte_spu(unsigned pinmask , unsigned data );
The touch_byte_spu( ) function sequentially writes eight bits of data on the 1-
Wire bus, just as the touch_byte( ) function does. The
pinmask defines which
pins are driven high when idle. The data defines the read or write data.
void touch_read_spu(unsigned pinmask , unsigned *dp , unsigned count );
The touch_read_spu( ) function reads a specified number of bits of data on the 1-
Wire bus, similar to the touch_bit( ) function. The pinmask defines which pins
are driven high when idle. The dp pointer defines the buffer into which the
function stores the read data. The count defines how many bits to read.
void touch_write_spu(unsigned pinmask , const unsigned *dp ,
unsigned count );
The touch_write_spu( ) function writes a specified number of bits of data on the
1-Wire bus, similar to the touch_bit( ) function. The pinmask defines which pins
are driven high when idle. The dp pointer defines the buffer from which the
function writes the data. The count defines how many bits to write.