Echelon I/O Model Reference for Smart Transceivers and Neuron Chips - Manual (Page 138)

128 Timer/Counter Input Models
For additional information regarding dualslope A/D conversion, see the Analog to
Digital Conversion with the Neuron Chip engineering bulletin (part no. 005-
0019-02).
Neuron C Resources
The following functions and events are provided for use with the dualslope input
model:
io_in_request( )
Starts the first step of the integration process. The control_value argument
controls the length of the first integration period.
io_update_occurs
Signals the end of the entire conversion process. The value at input_value
now contains the new measurement data.
Syntax
pin [input] dualslope [mux | ded] [invert] [clock ( const-expr )] io-object-name ;
pin
An I/O pin. Dualslope input can specify pins IO_4 through IO_7.
mux | ded
Specifies whether the I/O object is assigned to the multiplexed or dedicated
timer/counter. This field only applies, and must be used, when pin IO_4 is
the input pin. The mux keyword assigns the I/O object to the multiplexed
timer/counter. The ded keyword assigns the I/O object to the dedicated
timer/counter.
When the dedicated timer/counter is used, the control output pin will be
IO_1. When the multiplexed timer/counter is used, the control output pin
will be IO_0. The multiplexed timer/counter is always used for pins IO_5
through IO_7.
invert
Reverses the logical value of the input pin. Use this keyword if the
comparator output is high when the converter is in the idle state.
clock ( const-expr )
Specifies a clock in the range 0 to 7, where 0 represents the fastest clock and
7 represents the slowest clock. The default value is clock 0.
You can change resolution for the timer base clock frequency by calling the
io_set_clock( ) function with a clock value in the range 0..7 (using one of the
TCCLK_* macros defined in <echelon.h>). This function overrides the
resolution value specified for clock() within the I/O object declaration.
For an application running on a Series 5000 device, you can specify an
increased resolution for the timer base clock frequency by calling the
io_set_clock() function with a clock value in the range 0..15 (using one of the