Status Byte Definitions; Serial Poll Status Byte - Stanford Research Systems SR810 Manual

STATUS BYTE DEFINITIONS

The SR810 reports on its status by means of four status bytes: the Serial Poll Status byte, the Standard Event
Status byte, the LIA Status byte, and the Error Status byte.
The status bits are set to 1 when the event or state described in the tables below has occurred or is present.
SERIAL POLL
STATUS BYTE
The ERR, LIA, and ESB bits are set whenever any bit in both their respective status bytes AND enable
registers is set. Use the SSRE, SESE, ERRE and LIAE commands to set enable register bits. The ERR, LIA
and ESB bits are not cleared until ALL enabled status bits in the Error, LIA and Standard Event status bytes
are cleared (by reading the status bytes or using SCLS).
Using SSTB? to read the Serial Poll Status Byte
A bit in the Serial Poll status byte is NOT cleared by reading the status byte using SSTB?. The bit stays set
as long as the status condition exists. This is true even for SRQ. SRQ will be set whenever the same bit in
the serial poll status byte AND enable register is set. This is independent of whether a serial poll has occurred
to clear the service request.
Using SERIAL POLL
Except for SRQ, a bit in the Serial Poll status byte is NOT cleared by serial polling the status byte. When
reading the status byte using a serial poll, the SRQ bit signals that the SR810 is requesting service. The SRQ
bit will be set (1) the first time the SR810 is polled following a service request. The serial poll automatically
clears the service request. Subsequent serial polls will return SRQ cleared (0) until another service request
occurs. Polling the status byte and reading it with SSTB? can return different values for SRQ. When polled,
SRQ indicates a service request has occurred. When read, SRQ indicates that an enabled status bit is set.
bit name
0 SCN
1 IFC
2 ERR
3 LIA
4 MAV
5 ESB
6 SRQ
7 Unused
5-23
Remote Programming
usage
No scan in progress (Stop or Done). A Paused
scan is considered to be in progress.
No command execution in progress.
An enabled bit in the error status byte has been
set.
An enabled bit in the LIA status byte has been
set.
The interface output buffer is non-empty.
An enabled bit in the standard status byte has
been set.
SRQ (service request) has occurred.