Filter
Top Products
Chapter 2 125
Programming Fundamentals
Overview of the RS-232 Bus
Character Format Parameters
To define the character format, you must know the requirements of the
peripheral device for the following parameters:
• Character Length: Eight data bits are used for each character,
excluding start, stop, and parity bits.
• Parity Enable: Parity is disabled (absent) for each character.
• Stop Bits: One stop bit is included with each character.
Modem Line Handshaking
To use modem line handshaking for data transfer you would consider
the following tasks:
1. Set Data Terminal Ready and Request-to-Send modem lines to
active state.
2. Check Data Set Ready and Clear-to-Send modem lines to be sure
they are active.
3. Send information to the interface and thence to the peripheral.
4. After data transfer is complete, clear Data Terminal Ready and
Request-to-Send signals.
For ENTER operations:
1. Set Data Terminal Ready line to active state. Leave Request-to-Send
inactive.
2. Check Data Set Ready and Data Carrier Detect modem lines to be
sure they are active.
3. Input information from the interface as it is received from the
peripheral.
4. After the input operation is complete, clear the Data Terminal Ready
signal.