Product Overview
1. Differentiation between two models
PCI-7200: Standard 32-bit PCI bus industrial DIO card;
CPCI-7200: The specifications of the 3U CompactPCI industrial control chassis are consistent with the main functions, with an additional 4 auxiliary DI/DO channels, a larger 2K input FIFO, and a 100pin interface;
The underlying registers and driver APIs of the two are completely universal, and unless otherwise specified in the documentation, they are collectively referred to as PCI-7200.
2. Core positioning
32 TTL bidirectional digital IO channels, supporting 12MB/s bus main control DMA high-speed transmission, built-in 8254 timing counter, hardware handshake, internal and external triggering, suitable for high-speed digital pattern generators, external AD/DA synchronization, peripheral high-speed interfaces, BCD devices, pulse waveform output scenarios.
3. Core Highlights
32DI+32DO full TTL level, bus master DMA does not require CPU usage;
Maximum throughput of 12MB/s, built-in hardware FIFO buffer;
8254 three channel programmable timer, generating 0.00046Hz~2MHz sampling clock;
Four working modes: direct read/write, internal timing, external triggering, hardware handshake;
Interrupt, overflow/underflow hardware status detection;
DOS, Win95 dual platform C library+Windows DLL, supporting testing tool 7200UTIL.
Hardware electrical and specification parameters
1. Digital IO electrical (TTL compatible)
Input: Low level ≤ 0.8V, high level ≥ 2.0V; Input load low charging 0.6mA, high pulling 20 μ A;
Output: Low maximum 0.5V, high minimum 2.7V; irrigation current 24mA, pulling current 3mA, strong driving capability;
Auxiliary AUX I/O (cPCI-7200 only): 4DI+4TTL DO.
2. FIFO cache configuration
PCI-7200: 32 word (32-bit) on-chip FIFO for DI/DO;
CPCI-7200: on-chip 32 word+additional 2K depth DI FIFO, supports full/empty hardware flags.
3. 8254 timer counter (global clock 4MHz)
3 independent 16 bit counters Timer0/1/2:
Timer0: Sampling cycle of digital input;
Timer1: Digital output update rhythm;
Timer2: Can be cascaded with 0/1 and extended to extremely low frequencies;
Frequency division formula: Single timer 4MHz/division value, cascaded 4MHz/(Cx * C2), output range 0.00046Hz~2MHz.
4. Machinery, power supply, and environment
PCI-7200: size 98 × 147mm, power supply+5V 500mA, CN1 (40pin ribbon cable)+CN2 (37pin D-Sub) dual interface;
CPCI-7200: Standard 3U cPCI, power supply+5V 600mA, single 100pin SCSI interface;
Environment: Working at 0-50 ℃, storage at -20~80 ℃, humidity at 5-95%, no condensation.
5. Interface signal definition
Universal control signal (both models have):
I-TRG external input trigger, I-REQ input request, I-ACK input response;
OTR external output trigger, OREQ output request, OACK output response;
Handshake logic: REQ notifies external, ACK feedback board completes.
Key points of hardware installation chapter
Plug and play design: no dip/jumper, IRQ and I/O base addresses are automatically allocated by BIOS;
Installation requirements for static electricity: anti-static pad, anti-static wristband, check the chip before powering on;
Supporting cables: PCI version comes with a 40 to 37 pin cable; CPCI with 100 pin SCSI wiring harness;
Windows 95 driver installation process: A new device window pops up on the hardware, and the VXD driver is loaded on the specified CD X: Software 7200 Win95 path;
Test tool 7200UTIL.EXE: DOS/Windows dual end, capable of polling DIO, DMA mode, cPCI assisted IO function verification, automatically reading board card base address and interrupt number.
Interface pins:
PCI CN2(37pin):DI0~15、DO0~15、I_TRG/I_REQ/I_ACK;
PCI CN1(40pin):DI16~31、DO16~31、O_TRG/O_REQ/O_ACK;
CPCI 100 pin integrates all 32DI, 32DO, 4AUXD, 4AUXD, and all handshake trigger signals.

Register structure
The board occupies a continuous 32-bit I/O port, and cPCI adds an AUX register. Key registers:
Read and write three counters: Base+0/Counter0~Base+8/Counter2: 8254;
Base+C: 8254 control word register;
Base+10: Read only 32-bit digital input register;
Base+14: Readable and writable 32-bit digital output register (supports read back);
Base+18: DIO status control register (FIFO enable, trigger polarity, handshake switch, overflow/underflow flag);
Base+1C: Interrupt control/status register (I2REQ, OACK, timer interrupt enable and status bit);
CPCI Exclusive Base+20: Auxiliary DI/DO Register.
Key status position:
I-OVR: Input F overflow; ○UND: Output F underflow; Setting 1 requires software reset;
Interrupt source: Timer 0/1/2, I-REQ, O-ACK can be optionally enabled.
Four core working modes
1. Direct program control (polling mode)
The CPU directly reads and writes the Base+10/Base+14 registers, with a single read and write of all 32 channels, suitable for low-speed and low bit control.
2. Internal timer Pacer DMA mode
8254 generates a fixed beat, automatically locks DI/updates DO at the scheduled time, and transfers batch data to the system memory through the PCI bus main control DMA. The background automatically transfers the data, and the CPU only processes the entire block of data.
3. External I-REQ triggers DMA mode
External devices use hardware pulse locking DI through I-REQ, while the rest of the logic is synchronized with timing DMA for external AD/DA synchronous acquisition.