114 Agilent E1330B Digital I/O Module Register Information
Appendix B
Port Control/
Status Register
The Port Control/Status Register shows the status of STS, PIR, and FLG
lines. It also directly controls the RES, I/O and CTL lines.
STS
Bit 0 is read-only bit. Read this bit to find the status of the STS line, which
is an input from the peripheral for the port. A "1" shows that the line is
BUSY; a "0", shows that the line is READY.
PIR
Bit 1 is a read-only bit. This bit shows the normalized state of the PIR line,
which is an input line from the peripheral:
•
If positive-true logic is in use (bit 4 of the Port Normalization Register
is equal to "0"), bit 1 is equal to 0 if the line is low; "1" if the line is
high.
•
If the PIR line is inverted (bit 4 of the Port Normalization Register is
equal to "1"), bit 1 is equal to "0" if the line is high; "1" if the line is
low.
If peripheral interrupts are not enabled, you can use the PIR line as a
secondary status line. Just read bit 1 to monitor the state of the line.
If peripheral interrupts are enabled, you can still monitor the status of the
PIR line by reading bit 1. However, the current status of the PIR line does
not indicate whether a peripheral interrupt has occurred. Port peripheral
interrupts are caused by transitions in the state of the PIR line. Read bit 7 of
the Port Transfer Control Register to determine whether a port peripheral
interrupt has occurred.
Bits 2 and 3
Are not used.
FLG
This is a read-only bit. Read this bit to find the normalized status of the FLG
line. A "1" shows that the line is BUSY; a "0" shows that the line is READY.
This bit shows the logical state (BUSY or READY) of the FLG line,
regardless of the logic sense.
RES
This is a read/write bit. Reading this bit shows the current state of the RES
line which is an output line to the peripheral. A "1" shows that the line is
high; a "0" shows that the line is low. Bit 5 is initially set to "0" by a
hardware reset of the interface. This causes the RES line to go low, resetting
the peripheral, if the peripheral implements the reset feature. You can
control the logical state of the RES line by writing to this bit. Set bit 5 equal
to "1" to change RES to the high state. The peripheral will then operate
normally. To reset the peripheral, clear bit 5 to "0", putting RES in the low
state.
Port Address (0–3) base+10
16
, base +11
16
, base+12
16
, base+13
16
7
6
5
4
3
2
1
0
CTL
I/O
RES
FLG
—
—
PIR
STS
Summary of Contents for E1330B
Page 2: ......
Page 10: ...8 Notes ...
Page 11: ...9 Notes ...
Page 12: ...10 Notes ...
Page 32: ...30 Configuring the Agilent E1330B Digital I O Chapter 2 Notes ...
Page 42: ...40 Using the Agilent E1330B Digital I O Module Chapter 3 Notes ...
Page 58: ...56 Understanding the Agilent E1330B Digital I O Module Chapter 4 Notes ...
Page 104: ...102 Agilent E1330B Digital I O Module Command Reference Chapter 5 Notes ...