Echelon Neuron C - Manual (Page 164)

144 Functions
touch_byte( ) Built-in Function
The touch_byte( ) function sequentially writes and reads eight bits of data on a 1-
Wire bus. It can be used for either reading or writing. For reading, the
write-data argument should be all ones (0xFF), and the return value contains the
eight bits as read from the bus. For writing, the bits in the write-data argument
are placed on the 1-WIRE bus, and the return value normally contains those
same bits.
Syntax
unsigned touch_byte( io-object-name , unsigned write-data );
Example
void f(void)
{
unsigned dataIn, dataOut;
...
dataOut = 42;
dataIn = touch_byte(ioObj, dataOut);
}
touch_byte_spu( ) Built-in Function
This function applies to 1-Wire bus devices that require the bus to be actively
held high during certain device operations. These devices require more current
than a typical external pull-up resistor can provide for device operations. An
example of such a device is the Maxim Integrated Products DS18S20 High-
Precision 1-Wire Digital Thermometer. For other 1-Wire devices, use the
standard touch_byte( ) function.
The touch_byte_spu( ) function writes eight bits of data on a 1-Wire bus. Unlike
the standard touch_byte( ) function, this function cannot be used for reading
data. For writing, the bits in the data argument are placed on the 1-Wire bus,
and the bus is left in the actively driven high state.
Syntax
extern void touch_byte_spu(unsigned pinmask , unsigned data );
pinmask Specifies a single-bit representation for which I/O pins
IO0..IO7 to drive high when idle. Valid values are 0x01
(for IO0) to 0x08 (for IO7).
data Specifies the data to place on the 1-Wire bus.
Example
#define 1WIREPIN 0x02;
void f(void)
{
unsigned
dataOut;