2 serial and ieee terminator substitution, 3 ieee address selection – Measurement Computing Micro 488/EX rev.2.1 User Manual
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Section 6
Controller Pass-Thru Operation
6.2
If the IEEE device has been addressed to talk but does not respond or finish
transmission by the time additional characters are received into the circular serial input
buffer, the talk sequence will be aborted to allow additional serial information to be
sent to the IEEE device.
6.2 Serial and IEEE Terminator Substitution
The Micro488/EX can be configured to provide serial to IEEE 488 and IEEE 488
to serial terminator substitution. This is useful when interfacing a serial host which
only issues carriage return [CR] as an output terminator to an IEEE peripheral which
expects a carriage return followed by a line feed [CR-LF].
In this previous example, the serial terminator should be selected for CR Only
while the IEEE terminator is set for CR-LF. When a serial CR character is received it is
discarded and substituted with an IEEE CR followed by an IEEE LF. In the IEEE to
serial direction, the IEEE CR is unconditionally discarded. Upon receipt of the IEEE
LF
a serial CR is substituted.
The Micro488/EX can be made totally data transparent by setting both the serial
and IEEE terminators to be CR Only or LF Only. Refer to Section 2 for the proper
switch settings for both the IEEE and serial terminators.
6.3 IEEE Address Selection
SW3-1 through SW3-5 select the IEEE bus address of the IEEE peripheral the
Micro488/EX will be communicating with. In this mode, these switches set the
address of the IEEE device that will be controlled, not the address of the Micro488/EX.
The address of the Micro488/EX is automatically adjusted so that address conflicts will
not occur. The address is selected by simple binary weighting with SW3-1 being the
least significant bit and SW3-5 the most significant. If address 31 (reserved on the
IEEE bus) is selected in the controller mode, address 30 is assigned as the device it will
be communicating with. The following figure shows the IEEE address selection of 10.