ZENTRUM MIKROELEKTRONIK DRESDEN AG
“ASI for you” IC
Datasheet
3.6 Parameter Port and PST Pin
3.6.1 Slave Mode
The parameter port is configured for continuous bi-directional operation. Every pin contains an NMOS open
drain output driver plus a high voltage high impedance digital input stage. Received parameter output data is
stored at the Parameter Output Register and subsequently forwarded to the open drain output drivers. A certain
time (tPI-latch) after new output data has arrived at the port, the corresponding inputs are sampled.
The input value either results from a wired AND combination of the parameter output value and the signals
driven to the port by external sources (Multiplex_Parameter =’0’) or simply represents the externally driven input
signals (Multiplex_Parameter =’1’). For further explanation see also Figure 9 and chapter 3.6.2.
The availability of new parameter output data is signaled by the Parameter Strobe (PST) signal.
Besides the basic I/O function, the first parameter output event after an IC reset has an additional meaning. It
enables the data output at the Data Port (see chapters 3.7 and 3.11).
Any IC reset or the reception of a Delete_Address call turns the Parameter Output Register to 0xF and forces
the parameter output drivers to high impedance state. Simultaneously a Parameter Strobe is generated, having
the same tsetup timing and tPST pulse width, as new output data would be driven.
Table 16: Timing Parameter Port
Symbol Parameter
Min
0.1
0.1
0.1
5
Max
0.6
0.6
0.6
6
Unit Note
1
tsetupL
tsetupH
thold
Output data is valid LOW before PST-H/L
µs
1
Output driver is at high impedance state before PST-H/L
Output driver is at high impedance state after PST-H/L
Pulse width of Parameter Strobe (PST)
µs
1, 2
µs
3
tPST
µs
4
tPI-latch
Acceptance of input data
11
13.5
µs
1 The designed value is 0.5µs.
2 thold is only valid, if the Multiplex_Parameter flag is set in the Firmware Area of the E²PROM.
3 The timing of the resulting voltage signal also depends on the external pull up resistor.
4 The parameter input data must be stable within the period defined by min. and max. values of tPI-latch
.
tPST
tsetup
PST
data remains constant,
if Multiplex_Parameter
Hi-Z,
if Multiplex_Parameter
flag is
set
flag is
not set
parameter port output data
P0..P3
keep stable
thold
parameter port input data
tPI-latch
PI0..PI3
max
min
Figure 9: Timing Diagram Parameter Port P0 ... P3, PST
Copyright © 2006, ZMD AG, Rev.1.4
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The
Information furnished in this publication is preliminary and subject to changes without notice.
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ZMD [ Zentrum Mikroelektronik Dresden AG ]
