The Power1401 has full 16-bit digital input and digital output available on rear-panel D-connectors marked Digital Inputs and Digital Outputs. Bits may be read or written singly, by low or high byte, or by the whole word. High-byte output bits 0 and 1 are also routed to the front-panel Digital Outputs, and, if enabled by software, high-byte inputs 0 and 1 are fed from the front-panel Event Inputs.
The input high byte can be programmed for detection and timing of change of state (i.e. any bit changing in either direction). Digital output can be gated with clock 2 so that it updates on clock 2 ticks. Digital output is normally permanently enabled, but either byte may be turned tristate-off by software. It can also be controlled by pin 11 of the output socket. If pin 11 is grounded, both bytes are disabled, i.e. tristate-off ; they are enabled if pin 11 is high or disconnected.
Front-panel event-input LEDs flash on detection of active-edge transitions. The quiescent state is set by software command. Front-panel digital-output LEDs simply reflect the state of the bits, being lit whenever their bit is set (high).
Front-panel digital I/O is routed through common-mode ferrite chokes to prevent radiation of EMI. Outputs are buffered through 74ACT374s, which can source or sink 24mA.
Unconnected digital inputs read 1, being pulled internally to +5V by 4k7 (rear panel) or 100k (front panel) . Input voltages of more than 2.0V will always read as a logic 1. To appear as logic 0, the input must be pulled down to below 0.8V for at least 1microSec, which takes approximately 1mA (rear), 50microA (front).
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CED, through this site, does two things that relate to privacy. We would like to explain them.
We offer free down-loads of many files on our site, from test programs to complete install files for updated versions of major packages like Spike2 and Signal.
When customers wish to take a down-load of a major package, we ask a few questions, including their name, email address, the serial number of the software for which they seek an upgrade and whether they would like an automatic email whenever we update the product. This information is emailed back to CED when they access the final down-load screen. Within this email, your browser transmits the type and version of browser you are using, and the screen resolution you are running.
The reasons why we take and keep this information are that it is useful for our software development team to know who has taken the latest versions, and it is useful for our web site development team to know which browsers people are using to view our site, and what resolution they have their screens set to.
When people down-load a major package, we try to write a cookie, a small file in your computer, that records your name, serial number of the software package, and the version you are down-loading. These files have a lifetime of one year.
The reasons for storing this information are firstly that if you ask for another down-load some other time, your details are read from the cookie and are pre-written into the form, to save you looking them up again. The other reason is that next time you access our site, your browser looks through your CED cookies and compares the versions down-loaded with the latest version numbers read from our site. If there is a later version of a product you have already down-loaded, we tell you on the home page screen, so you know that it is worth going to the down-load page again.
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