PC Serial Port Drives 12-bit A/D Converte
Abstract: This application note provides an example of interfacing an A/D converter to a PC using a standard serial port. The CS lines and SCLK lines are emulated by the RTS and DTR lines respectively. Conversion data appears on the data-set-ready (DSR) line.
Example C
code is given to demonstrate the application circuit.
The circuit shown in Figure 1 performs a task usually carried out by a microcontroller—that of driving a 12-bit A/D converter (ADC) from the serial port of a PC. Power consumption is low: The 2mA operating current drops to only 15µA in shutdown.
Figure 1. This micropower circuit enables a PC´s RS-232 serial port to control a 12-bit A/D converter (IC3).
Interface to the PC is an RS-232 port rather than the transmitter/receiver lines of a UART. The port´s request-to-send (RTS) line provides a chip-_select_signal, and its data-terminal-ready (DTR) line provides a synchronous-clock signal. A single-supply RS-232 interface chip (IC1) converts these signals from RS-232 levels to CMOS-logic levels (and inverts them in the process). Conversion data appears on the data-set

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Keywords :
PC,
Serial,
Port,
Drives,
12-bit,
A/D,
Converte
Writer : delon |
2 Feb 2011 Wed  
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