Ampro Corporation 486E manual Serial Console, Hex Command

Little Board™/486e Technical Manual

Multidrop Network

More than two devices share an RS-485 signal pair, for both transmission and reception of data. Only one device is permitted to talk at any one time. As with simple bi-directional communication, the board’s RS-485 transceiver is placed in receive mode unless it is the one permitted to transmit. One popular way of managing who is the transmitter is by a “token” passing scheme. Each node is assigned an ID number. Whoever transmits also sends the ID of the next node allowed to transmit. If a node does not need to transmit, it just immediately sends the “token” to its next node. This simple scheme is easy to implement and trouble free. Time-outs can be implemented in software to prevent a lockup should a node fail to pass the token properly.

Serial Console

Ampro’s unique ROM BIOS support for a serial console consisting of a keyboard and display replaces conventional video controllers, monitors, and keyboards. To use the serial console features, connect the serial console device(s) to Serial 1 or Serial 2. Use SETUP to configure the

Little Board/486e CPU to use its serial console support feature. The configuration memory stores serial console configuration parameters.

Caution

Be careful when changing the console configuration using SETUP. If you specify “None” for console input and output, there is no console access to the system. (You can recover from this state by removing the serial console plug from the primary serial port connector and shorting pins J11-7/8.)

SETUP provides separate configurations for serial console input and outputs (I/Os) so that either input or output or both input and output are possible from any serial port and it’s attached serial device.

To use an ASCII terminal as the console device for your system, set both the I/O parameters to Serial Port 1 (or 2), and set the serial baud rate, data length, and stop bits to match the setting of your terminal. For proper display of SETUP and POST messages from the BIOS, you must use an IEEE-compatible terminal that implements the standard ASCII cursor commands. The required commands and their hexadecimal codes are listed in Table 2–14.

Table 2–14. Required Commands

Hex	Command
08	Backspace
0A	Line Feed
0B	Vertical Tab
0C	Non-destructive Space
0D	Carriage Return

2–18