Measurement Computing Analyzer488 - Manual (Page 100)

Section 4 Serial Controller
4.6
Byte 2, (F4) Data Lines
F4= (%11110100)
Lines DIO8 through DIO5 are asserted, DIO3 is asserted.
4.9 Record Memory Format
The bus events stored in the record memory can be seen using the VIEW or
DUMP commands. The VIEW Record command returns events from the record
memory in blocks. The DUMP Record command returns the contents of the record
memory in S1S9 record format (See the DUMP command description for details of
S1S9 format). Record memory events are returned in two hex bytes and are formatted
as follows:
Byte 1 Byte 2
(bit positions) (bit positions)
(Control and Status Lines) (Data Lines)
8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1
REN IFC SRQ EOI BERR VALIDTRIG ATN D8 D1
A response of 84F4 is interpreted as follows:
Byte 1, (88) Control and Handshake Lines
Upper nibble (8) (%1000)=REN asserted
Lower nibble (4) (%0100)=this data is valid.
Byte 2, (F4) Data Lines
F4=(%11110100)
Lines DIO8 through DIO5 are asserted, DIO3 is asserted.
4.10 Memory Usage
Memory in the Analyzer488 is dynamically allocated for the serial input and
serial output. This allows for the most efficient partitioning of memory for any given
application.
At power on, each serial buffer is allocated a 127 byte mini-buffer or queue.
When the serial input [or output] requires more buffer space, additional queues are
allocated. When a queue is empty, it is released from the input buffers so that it may
be reallocated when, and where, required.