Справочник Пользователя для Bay Technical Associates 528H
Mode of Operation 6 provides time-division multiplexing. In this
mode, the multiport continuously scans all peripheral ports to check
for characters in the receive buffers. If a receive buffer contains data,
the data is transmitted to the host device preceded by a port
identification code corresponding to the peripheral port number from
which the data block came. Transmission continues until the buffer is
empty or until a user-specified data block length has been
transmitted.
mode, the multiport continuously scans all peripheral ports to check
for characters in the receive buffers. If a receive buffer contains data,
the data is transmitted to the host device preceded by a port
identification code corresponding to the peripheral port number from
which the data block came. Transmission continues until the buffer is
empty or until a user-specified data block length has been
transmitted.
A typical application using an H-Series multiport controller would have
a host computer, such as an IBM PC, connected to the host port, and
various peripheral devices (such as cash registers, digital laboratory
instruments, bar code readers, numerical machines, printers,
modems, terminals, etc.) connected to the peripheral ports.
a host computer, such as an IBM PC, connected to the host port, and
various peripheral devices (such as cash registers, digital laboratory
instruments, bar code readers, numerical machines, printers,
modems, terminals, etc.) connected to the peripheral ports.
Regardless of the mode of operation, the host device may connect
and send data to a specific peripheral port by sending the control
character and the desired peripheral port number followed by the
data. The control character and peripheral port number are trapped
and therefore not passed through to the selected peripheral port. For
demonstration purposes, we will use the default control character,
Control-T.
and send data to a specific peripheral port by sending the control
character and the desired peripheral port number followed by the
data. The control character and peripheral port number are trapped
and therefore not passed through to the selected peripheral port. For
demonstration purposes, we will use the default control character,
Control-T.
NOTE: The 8th bit or parity bit is masked from the control character
before it is examined, allowing you to send the control character with
odd or even parity. Therefore, when 8 data bits are being sent, only
the first seven data bits are examined.
before it is examined, allowing you to send the control character with
odd or even parity. Therefore, when 8 data bits are being sent, only
the first seven data bits are examined.
In modes of operation 2 through 5, each message sent to the host
device is preceded by the port number of the peripheral port that
received the message. This number may range from 1 to 4 on the
525H, 1 to 8 on the 528H and 529H, and 01 to 17 on the 5218H.
device is preceded by the port number of the peripheral port that
received the message. This number may range from 1 to 4 on the
525H, 1 to 8 on the 528H and 529H, and 01 to 17 on the 5218H.