ZBasic System Library
74
ZBasic Microcontrollers
Type
Subroutine
Invocation
Com1toDAC(pin)
Parameter
Method
Type
Description
pin
ByVal
Byte
The pin number on which the analog voltage will be re-created.
Discussion
Calling this subroutine prepares Com1 to receive a continuous stream of 8-bit values from an external
source. The baud rate is automatically set 115,200. When each value is received, the value is output as
an analog voltage on the specified pin. The resulting analog voltage will range from near 0 volts
corresponding to the received value of 0 to near the processor voltage (usually +5 volts) corresponding to
the received value of 255. The method used to create the analog voltage is similar to that used for
PutDAC() and the signal will require some filtering. See the description of PutDAC() for more details.
The output pin is updated at a fixed rate of 11,000 times per second.
This routine returns immediately after setting up the conversion process. The conversion process will be
terminated if Com1toDAC() is called again with a parameter of zero. Also, if data is not received for
approximately 200 cycles, the conversion process will be automatically terminated.
Note that the subroutine ADCtoCom1() is designed to produce the data stream to be received by this
subroutine.
Resource Usage
This subroutine uses Com1 and the I/O Timer. No other use of these resources should be attempted
while the reception is active. For native code devices, the following ISRs are automatically loaded.
ISRs Required
Underlying CPU
ISR Name
mega328P, mega644P, mega128
Timer1_CompA
mega1284P
Timer3_CompA
mega1281
Timer4_CompA
mega1280
Timer4_CompA
Compatibility
This subroutine is only available on ATmega-based ZX devices.
See Also
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