Timer; External Clock Input/Output - Measurement Computing USB-1808X-OEM User Manual

USB-1808X-OEM User's Guide

Timer

Parameter
Terminal name
Timer type
Output value
Trigger source
Internal clock frequency
Register widths
High pulse width
Low pulse width
Output high voltage
Output low voltage
Output current

External clock input/output

Parameter
Terminal names
Terminal types
Terminal descriptions
Input clock rate
Clock pulse width
Input type
Schmitt trigger hysteresis
Input high voltage
Input low voltage
Output high voltage
Output low voltage
Output current
Table 13. Timer specifications
Specification
TMR0, TMR1
PWM output with count, period, delay, and pulse width registers
Default state is idle low with pulses high, software-selectable output invert
OTRIG (see External trigger on page 24)
100 MHz
32-bit
10 ns min
10 ns min
4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –2.5 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 2.5 mA)
±2.5 mA max
Table 14. External clock I/O specifications
Specification
ICLKI, ICLKO
OCLKI, OCLKO
xCLKI: Input, active on rising edge
xCLKO: Output, power on default is 0 V, active on rising edge
xCLKI: Receives sampling clock from external source
xCLKO: Outputs the internal input scan or internal output scan clock, or the
pulse generated from xCLKI when in external clock mode.
500 kHz max
xCLKI: 400 ns min
xCLKO: 400 ns min
Schmitt trigger, 33 Ω series resistor, 47 kΩ pull-down to ground
0.4 V to 1.2 V
2.2 V min
5.5 V absolute max
1.5 V max
–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –2.5 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 2.5 mA)
±2.5 mA max
23
Specifications