21 | Keysight | 34980A Multifunction Switch/Measure Unit - Data Sheet
Frequency counter/totalizer
34980A System Control Modules
The two channels can be used to count
digital events, frequency, period, duty
cycle, totalize, and pulse width. The
counter/ totalizer also includes
– Programmable gate functionality
– Programmable input thresholds
levels 0 V to 3 V
34950A 64-bit digital I/O with memory and counter
This module can be used to simulate or detect digital patterns. It has eight 8-bit digital
I/O channels with handshaking, pattern memory, two 10 MHz counters with gate func-
tions, and a programmable clock output.
Digital input/output
Digital input/output characteristics
The digital I/O bits are organized into two banks of 32-bits. The I/O bits can be conꢁg-
ured and programmed as inputs or outputs in 8-bit channels. The digital outputs can be
conꢁgured as active drive or open drain outputs with a 10 kΩ pull up. User supplied pull
up resistors for up to 5 V outputs are also acceptable. The digital inputs have program-
mable thresholds up to 5 V for compatibility with most digital logic standards.
Eight 8-bit channels:
8 bits wide, input or output, non-isolated
Vin
0 V – 5 V [1]
Vout
Iout
1.65 V – 5V [1, 2]
(max) 24 mA [2]
The onboard pattern memory can be used to select and output digital stimulus or bit-
stream patterns, or to capture external digital data. Each bank has independent memory
and directional control so that one bank can output data while the other captures data.
The memory can be divided up to 64 Kbytes per 8-bit channel.
Frequency (max) 10 MHz [3]
ILoad (max)
trise + tfall (typ)
Handshake lines
Vin
400 mA
6 ns [5]
Speciꢁcally, the digital I/O channels also have:
– Variable active high drive output from 1.65 V to 5 V or open drain
– Variable input thresholds from 0 V to 5 V
– Conꢁgurable handshaking protocols including synchronous, and strobe
– Programmable polarity
0 – 5 V [4]
Vout
1.65 – 5 V [2, 4]
24 mA [2]
I out (max)
Frequency (max) 10 MHz
– Source or sink up to 24 mA with a Imax of 400 mA per module.
– Internal alarming for maskable pattern match
– 1 hardware pattern interrupt per bank
Counter function characteristics
Max freq
10 MHz (max) 50%
duty cycle
– Connections via standard 78-pin Dsub cables or detachable terminal block
Vin
0 V – 5 V
Min rise/fall time 5 μsec
Totalizer function characteristics
Maximum count 2^32 – 1
(4,294,967,296)
Max input freq
10 MHz (max), rising
or falling edge
programmable
Vin
0 V – 5 V
0 V – 5 V
Gate input
Min rise/fall time 5usec
System clock generator characteristics
Frequency
20 MHz – 10 Hz
conꢀgurable
divideby-n 24-bits,
programmable on/off
Vout
1.65 V – 5 V [2]
24 mA [2]
I out (max)
Accuracy:
100 ppm
[1] Configurable by 8-bit channel
[2] Lower current drive at lower voltages
[3] From memory with handshaking
[4] Configurable by bank
[5] 5 V, 50 pF load
Figure 13. 34950A 64-channel digital I/O
KEYSIGHT [ Keysight Technologies ]
