Programmable Analog Inputs
A total of 24 A-D inputs are available from two converters.  The first one has 8 channels at 10 bit resolution.  Input voltage is 0 to 5V maximum.  A 2.5V reference is available for lower voltage inputs.
Conversion is initiated by an external or internal trigger and is completed in under 7uS.  A scan mode converts four channels continuously.  Thus, you can read four of the latest conversions as fast as the CPU can read it (under one uS).

The second A-D converter has up to 8 differential or 16 single ended programmable inputs at 12 or 16 bit resolution.  Any combination of differential and single ended signals may be applied.   Input ranges at X1 gain is 0-5V or +/- 5V.  16 software programmable gains from X1 to X800 amplify signals as low as 6.25 mVFS.  Differential inputs allow direct connection to load cells.  Connect thermistors directly with minimal self heating.  A shield driver output reduces signal noise in cables.

Conversion time is 10uS for 12 or 16 bit resolution.  Settling time (changing channel)  for 12 bit resolution is 30uS.  To obtain accurate 16 bit readings, several measurements are made on a channel.

Both converters can interrupt when conversion is complete.   Development systems and boards are available with 12 or 16 bit converters. 

Flexible Analog Output
Up to 4 D-A voltage or 4-20 mA current outputs are optionally available (included in the development systems).  Part number 1454 supplies a voltage output for one D-A channel.  Resolution is 12 bits.  Voltage ranges are jumper selectable for 0-5V, 0-10V, or  +/-5V.  D-A outputs can drive about 5mA and still retain good accuracy.  Part number 1678 is a kit of IC's for 4-20 mA output.  External power of at least 13V is required for current loop operation.

Either development system includes four D-A and 4-20 mA outputs.  When ordering a board only, D-A and 4-20 mA outputs are not included.

  Digital I/O
37 digital I/O lines interface with 0-5V switch and sensor inputs or drive opto racks.  These lines are divided into groups described below.

24 lines are from an 82C55.  These lines directly drive opto racks and have a high current output.   Lines are programmed for inputs or outputs in groups of four or eight.  Eight of these lines can drive relays, lamps, and other loads rated to 50V at 250 mA.  The high current output can be replaced with jumpers to make it an input or standard TTL output.  A CMA-26 cable connects the port to a STB-26 board for easy access.  They can also be connected to MPS-08,  -16, or -24 opto racks to read or control high voltage lines.

Another 13 lines are from the CPU.  These lines are individually programmable as digital I/O, timer I/O, or interrupt inputs.  Use the STB-20 with CMA-20 cable to bring lines out to screw terminals. 

An additional group of 24 lines are also available if the keypad or display is not used.  The keypad uses 10 lines while the display uses the rest.  Using these ports brings the total number of digital I/O lines
available to 61.

The keypad and display ports use an 82C55.  Lines are programmable for inputs and outputs in groups of four or eight. 

24 Bit Multimode Counters
Up to four multimode counters are programmable to read a quadrature output or 20 MHz signal inputs.  They can be programmed to interrupt when a specific count is reached.  One counter has two high voltage (up to +/-24V) inputs (up/down count).  A counter is used in conjunction with pulse width measurement described below. 

Quadrature Encoder Inputs
Up to 4 quadrature encoders may be connected to the RPC-400.  The encoders include a programmable filter to eliminate noise from the quadrature clocks.  Quadrature modes are programmable for X1, X2, and X4.  The counter is programmable to mimic limit switches by setting a lower and upper limit.  Interrupts can be generated when any limit is met.  One input has high voltage (+/-24V) inputs to directly connect high voltage interfaces.  Counting speed is limited to 1 Mhz.  

Pulse Width Measurement
Four kinds of pulse or cycle timing can be made on two of the counter input channels.  The counters can be programmed to measure a positive or negative pulse from starting to ending edge.  They can also measure the period of one cycle starting with the rising or falling edge.  Measurement precision is 203.45 nS.  An
interrupt can be generated when a measurement is completed.  Maximum pulse or cycle time is about three seconds.  Additional pulse width measurements are possible. 

An additional quadrature input is available.  This input is unfiltered and goes directly to the CPU's 16 bit counter.

16 Bit Timer-Pulses
 In addition to the four hardware counters, the CPU has four channels of 16 bit timers available.  These lines can process several kinds of pulse outputs and inputs.  These include: PWM output with any duty cycle, measure pulse widths up to 50.8 nS resolution, and general timing.  All timers can generate an interrupt.

Operator Interface
LCD character and graphic displays connect directly to the RPC-400 card.  The graphic display uses the expansion bus port while the character display has its own connector.  Graphic and character displays can operate simultaneously.

 An operator can input data through a 16 position KP-3 keypad.  A 4 X 6 scan matrix is available for larger keypads. 

Serial Ports
Up to four serial ports are available.  Three are RS-232, non isolated.  A fourth port is isolated RS-232 or RS-422/485.  All RS-232 ports support TxD, RxD, CTS, and RTS lines.  The two optional serial ports are PC compatible and have DB-9M connectors for RS-232.  All serial ports are programmable for 7 or 8 data bits, 1 or 2 stop bits. 

 Two channels are programmable for baud rates from 110 to 38,400, 7 or 8 data bits, parity (O, E, or None), and one or two stop bits.  The two additional ports use a PC compatible 16C550 UART and are
programmable for any rate and parameters a PC can do.

The isolated RS-485 port uses a low power interface chip.   Consequently, more than 32 devices may be connected on a network.  Isolated RS-232/485 ports are available on boards with four serial ports only.

Memory
There are four types of memory.  The CPU has 8K bytes of RAM.  256K of high speed RAM is used to run the program.  A 32K or 512K flash EPROM is used for program and data storage.  Programs may be changed in the field through a laptop or modem.  An additional socket for 128K or 512K RAM is available for data or program storage and is battery backable.  

Real Time Clock
An optional real time clock with battery back up may be installed at anytime.  An optional 128K or 512K RAM may be installed in the real time clock to retain data on power off.  Use the DS1216DM (128K RAM) or DS1216D512(512K RAM). 

Interrupts
Several interrupts may be generated both on and off card.  Internal interrupts include those from the A-D, counters, timers, and serial ports.  Five external lines are available as edge or low level sensing interrupts.

Watchdog Timer
The CPU has a programmable watchdog timer which resets the CPU upon overflow.  Hardware is not affected, as it is treated like an interrupt.  It can be programmed to restart the program or take whatever action is necessary.

CPU
The RPC-400 uses a RISC type CPU, the SH-1 from Hitachi.  Most instructions execute in one clock cycle(50 nS).  The CPU has a 32 bit internal architecture and accesses instructions on a 16 bit bus.  The CPU instruction set includes a MAC instruction which executes in 3 cycles (150 nS).  Signed and unsigned multiply and divide execute in 1 cycle as do other arithmetic instructions.  The C development program, included with the development system, is based on GNU C compiler.

The CPU includes two serial ports, watchdog timer, 5 timers, A-D converter, and 9 interrupt lines, 6 of which are available externally.

Development Systems
Development systems provide the software and accessories to get up and running quickly.  Systems include a desk top power supply, serial cables, hardware manual, C compiler, assembler, and source level debugger from GNU, programming manuals, programs, board schematic, and source disks.  The environment runs under DOS, so you will need a PC with at least one serial port.  You can run in a network environment, such as Windows (R) 95.

Development Environment
A PC DOS compatible C compiler is included with the development system.  Sample programs, with MAKE and batch files, help getting started fast. 

The development cycle starts by writing and compiling the program on a PC.  The debugger, included with the development system, downloads code to the RPC-400 and allows single step and program breaks.  When the program is complete, it is saved to on card Flash EPROM using a command in the BIOS.  When the autorun jumper is removed, the BIOS transfers the program to RAM and program execution begins upon reset or power up.

DMA
DMA may be used to quickly transfer information to or from memory to CPU internal functions such a s serial communications, A-D converter, and timers.

Expansion Bus
 A simple expansion bus provides 8 data, 5 address lines, port select, and one interrupt for external devices.

Technical Specifications

Processor:
SH7032 RISC engine operating at 19.6608 Mhz.  Instruction cycle time is 51 nS.

Analog Inputs:
10 bit converter
Channels:     8
Range:          0-5 V max.  Depends upon reference input.
Resolution:     10 Bits
Input resistance:   100K
Conversion time: 6.7 uS

12 and 16 Bit Converter:
Range:    0-5V or +/-5V at X1 gain, software programmable
Overvoltage protection: to +/-32V
Maximum differential offset:  12 VDC
Channels:   8 differential, 16 single ended, software programmable.
Gains:         Software programmable in 16 steps from 1 to 800
Resolution:  12 or 16 bits, depending upon board
Input resistance:   1 M
Conversion time:   < 10 uS
Settling time:         < 30uS
ENOB:     11.3 (12 bit), 13.5(16 bit)

Analog Outputs:
Channels:    4
Type:           Voltage and 4-20 mA current
Voltage range:    0-5, 0-10, +/-5 volts
Resolution:   -12 bits

External power required for loop current.

Digital I/O:
48 lines from 82C55.  Another 13 lines are available from the CPU.  8 are buffered through a high current port.  4 lines are programmable for PWM output.

Multimode Counters:
Number:    4     
Range:          24 bits
Max. freq:    20 MHz
Inputs:          Quadrature single ended, 1 high voltage, others TTL levels               
Interrupts:     Carry, borrow

Power Requirements:
+4.75 to 6V at 400 mA
+13 to +16V at 50 mA
-13 to -16V at 50 mA
External supply required for loop current

Environmental:   
0 degrees C to +75 degrees C
Extended temperature ranges available.

Mechanical:  
Size: 6" X 10"
Mounting: 0.156" holes, 0.25" from edges.