Port Adapter. DS1410E Datasheet
Parallel Port Adapter
§ Provides a parallel port interface for Dallas iButtons
§ Compatible with low-power parallel ports
§ No external power required
§ Operates with DOS, Windows, Windows 95, Windows
NT, SCO UNIX, UNIXWARE, and HP_UX for
The DS1410E Parallel Port Adapter interfaces Dallas Semiconductor Authorization iButtons to host
computers via a PC parallel port. In conjunction with the iButton, the DS1410E provides a high security
storage vault for critical execution control information. Only users who posses an iButton can utilize the
software, preventing execution of unauthorized copies.
The modularity of the DS1994 allows for easy feature customization. The device supports the insertion of
two iButtons, which can be removed and replaced to vary functionality.
For example, a DS1994 Time iButton can be programmed for a 30-day expiration, issued with a
DS1410E and a software copy. The evaluator can be converted into a registered user by issuing a DS1991
Multi iButton and inserting it into the second receptacle. The DS1410E supports the same iButtons as
other Dallas port adapters. This allows standardization of any protection scheme across virtually all
hardware platforms, regardless of the operating system. The iButtons remain constant, and the port
adapters change according to the specific platform interface.
The DS1410k Development Kit contains access system software which must be linked with the
application software in order to complete integration. The support for the application development
environments and operating systems lies in the interface software of the access system. The access system
contains the low-level interface for communicating with the iButtons.
The DS1410E utilizes a DS1481 1-WireTM Bus Master to communicate with iButtons. The DS1481
generates either a read/write bit “time slot” or a reset on the I/O pin (1-Wire bus). The operation
performed is determined by the states of input pins 2 and 3 on the port adapter as follows:
Read 0, Read1, Write 1
logic high(see Figure 1)
logic high (see Figure 2)
logic low (See Figure 3)
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After input pins 2 and 3 have been set, the time slot begins by driving input pin 14 to its active state
(low). A falling edge on input pin 14 causes the DS1481 to drive input pins 11 and 13 low (indicating a
time slot is in progress).
While input pins 11 and 13 are low, the host processor is free to perform other tasks (including running
the print spooler). When the time slot is complete input pins 11 and 13 are restored to the states of output
pins 11and 13.
When the host detects that one or both of the busy signals has returned high, it must query the result of
the time slot. This is accomplished by driving input pin 2 low. If the 1-Wire bus was low (read 0, write 0,
or presence detect) the DS1481 drives both input pins 11 and 13 low (this state was held until input pins
14 or 2 return high). Otherwise it propagates the states of output pins 11 and 13.
After the host reads the time slot result it must drive input pin 14 to its inactive state (high). The DS1481
will then set input pins 11 and 13 to the state of output pins 11 and 13.
DS1410E 1-WIRE TIMING GENERATION
For all time slots, the DS1481 samples the I/O pin
www.Dat6a0Sµhesefrt4oUm.cthoemstart of the time slot and de-asserts
at tSIO (see Figure 3).
input pins 11 and 13.
When a reset is requested, the DS1481 drives the I/O pin low for at least 480 µs and then releases it.
During a normal reset the I/O pin immediately begins to return high.
If a 1-Wire device is present on the I/O line it pulls I/O low after time T (15 µs ≤T ≤60 µs) from the
previous rising edge. The 1-Wire device(s) holds the I/O line low for 4T and then releases it, allowing the
I/O line to return high. This is the presence detect pulse. The I/O line must remain high (in its idle state)
for at least 3T before the 1-Wire device(s) is ready for further communication. To insure this idle high
time is satisfied, the DS1481 does not release input pins 11 and 13 for at least 960 µs (measured from the
1st falling edge on the I/O pin).
If after 480 µs of low time the I/O line did not return high, either the I/O line has been shorted to ground
or there is at least one 1-Wire device connected to the I/O line which is issuing an alarm interrupt (see
Figure 3). In this case the DS1481 waits for I/O to return high for an additional 3840 µs (64 * 60). If time
expires the I/O line is assumed to be shorted and the DS1481 releases input pins 11 and 13. If the I/O line
returns high, the DS1481 continues to monitor the presence detect portion of the reset (as described
above) as for the non-interrupt case. Note that the 3T idle high time is still required after the presence
The DS1481 also supports overdrive communication with overdrive capable 1-Wire devices. When the
DS1481 powers up it is in normal mode (i.e., OD = 0, Figure 1). To toggle to overdrive mode the host
sets input pins 2 and 3 low and drives Input pin 14 low. The DS1481 toggles the OD (OverDrive) bit to a
logic high and returns the states of output pins 11 and 13 on input pins 11 and 13. Overdrive mode is
cleared in the same way. When Overdrive is turned off (OD = 0). Input pins 11 and 13 are driven low to
report the state of the OD bit.
When OD = 1, communication with the 1-Wire devices is exactly as described in the operation section
above. The actual 1-Wire timing for both modes of operation is described in figures 1, 2 and 3 below.
Note that when toggling the OD bit there is no change on the I/O line.
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