Hytec Electronics Ltd.
 

Data Acquisition and Control

 PCI 5221 DIGITAL INPUT INTERFACE

Introduction 

This card is a Universal PCI card to PCI specification rev. 2.2 with 32 opto-isolated digital inputs with contact de-bounce and change-of-state detection.

Functions

The card uses a PLX Technology PCI9030 bridge chip to handle and decode PCI transactions. The card requests an area of I/O space into which it decodes read and write commands for on-board resources.

Mode of Operation

The card presents registers 16 bits wide to the PCI bus in pre-defined positions.

In the case of the PCI5221 input card, reading two 16-bit registers will give the last known state of the 32 input signals. A bit in one of these registers showing a ‘1’ will denote that the corresponding input is energised. The hardware scanrate may be controlled by writing to a third register, the rate may be set from 20Hz to 250Hz, the default rate is 100Hz. The input states are further processed by being de-bounced at the sampling rate. The de-bounce works by requiring three consecutive samples of the input signal to be different from the stored state, at which point the ‘current known state’ is updated to the latest sample state for all 32 bits.

Signal Levels

The inputs will be protected against over-voltage and reverse voltage and will expect an operating signal of 24 volts, although they will work down to below 12 volts.

PCI Bus Interface

Important note: This card is a 32-bit PCI cards for 3.3 or 5-volt signalling systems. It requires +3.3 volt power to be present on the motherboard connectors. Being a Universal PCI card, it will fit in either a 5-volt 32-bit PCI slot, or a 3.3-volt 32 or 64-bit PCI slot.

When the card is fitted into a PC, the BIOS will detect and assign resources as requested by the card. The resources are in the form of I/O and memory areas. One of the I/O areas is used for access to the on-board registers described above. It is the responsibility of the host software to determine the base address for this I/O area using the card’s manufacturer and model identifiers. Hytec’s manufacturer ID is 1196h and the board’s model number ID is 5221h for the input card.

Registers

 [‘R/W’ means writeable and readable; ‘WO’ means write only; ‘RO’ means read only].

The input card will have three main functional registers. [Other registers discussed below].

Offset           Function

0h                Inputs 1 to 16 (RO)

2h                Inputs 17 to 32 (RO)

4h                Scanrate: 16-bit R/W register in which only the least significant 3 bits have any function for setting the input scanrate (20– 250Hz):

 

Data (bin.)     Scan rate selected

000              100Hz                     (Default at power-up)

001              20Hz

010              31Hz

011              50Hz

100              62Hz

101              125Hz

110              200Hz

111              250Hz

Connections

The 5221 card uses a 68-way SCSI-III high-density connector with signals arranged so that they run along twisted pairs in a SCSI-III cable.

Pin(+)  Pair (-)          Function 

1        35                Signal circuit 1.

2        36                Signal circuit 2.

3        37                Signal circuit 3.

4        38                Signal circuit 4.

5        39                Signal circuit 5.

6        40                Signal circuit 6.

7        41                Signal circuit 7.

8        42                Signal circuit 8.

9        43                Signal circuit 9.

10      44                Signal circuit 10.

11      45                Signal circuit 11.

12      46                Signal circuit 12.

13      47                Signal circuit 13.

14      48                Signal circuit 14.

15      49                Signal circuit 15.

16      50                Signal circuit 16.

17      51                Signal circuit 17.

18      52                Signal circuit 18.

19      53                Signal circuit 19.

20      54                Signal circuit 20.

21      55                Signal circuit 21.

22      56                Signal circuit 22.

23      57                Signal circuit 23.

24      58                Signal circuit 24.

25      59                Signal circuit 25.

26      60                Signal circuit 26.

27      61                Signal circuit 27.

28      62                Signal circuit 28.

29      63                Signal circuit 29.

30      64                Signal circuit 30.

31      65                Signal circuit 31.

32      66                Signal circuit 32.

The (+) and (-) indications above refer only to the input configuration where the polarity of the input voltage is relevant.

Additional Registers

For test and diagnostic purposes, both cards have other registers which are not normally used. These are intended for Hytec test use only:

PCI5221 input card

Offset           Function

8h                Debounce Inhibit – inputs 1-16 (bit 0 corresponds to input 1). (R/W)

Ah                Debounce Inhibit – inputs 17-24 (bit 0 corresponds to input 17). (R/W)

A ‘1’ in a bit position means ‘do not debounce’. All bits default to ‘0’ at power-up.

Ch                Simulate Test inputs – inputs 1-16 (bit 0 corresponds to input 1). (R/W)

Eh                Simulate Test inputs – inputs 17-32 (bit 0 corresponds to input 17). (R/W)

Any bit set to ‘1’ in either of these registers enables the test outputs, so all must be at ‘0’ to enable external signals to be input. This is the default state at power-up

 

10h              Configuration ROM, catalogue number 5221 decimal. (RO)

12h              Xilinx version number, ‘1’ at the time of writing. (RO)

14h              Xilinx revision number, ‘1’ at the time of writing. (RO)

12h              Configuration checksum. Sum of four registers should be hex FFFF. (RO)

Indicators

In order to assist commissioning, the cards are fitted with LED indicators as follows:

PCI5221 Input Card:

 This card has one LED:

A yellow LED which flashes to show that the card has been addressed. 
 

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Phone : +44 (0)118 9757770
Fax : +44 (0)118 9757566

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Last modified: September 24, 2008