



Manufacturer /Part 



Number Used 



Type 



Number 



1 



Microprocessor card (4 kilobytes 

 of PROM) 



Prolog 8821 



1 



TTL input buffer card (4 inputs) 



Prolog 8114 



1 



TTL output latch card (4 outputs) 



Prolog 8116 



1 



8-bit A/D converter card (16 inputs) 



Burr Brown MP4216 



1 



12-bit A/D converter card (16 inputs) 



Analog Devices RTI-1220 



2 



8-bit D/A converter card (2 outputs) 



Burr Brown MP4102 



2 



Relay output card (8 switches) 



Prolog 8402 



1 



16k ROM/RAM card (using Texas 

 Instruments 2716 PROMs) 



Prolog 8820 



1 



4k CMOS RAM card 



Prolog 8122 



1 



Serial communications (UART) card 



RIIJLI COM 412 



1 



Interface control card 



NOSC 



Table 3. Printed Circuit Cards for the Vehicle Microprocessor System. 



The microprocessor is used to compare programmed run time, heading, 

 depth, and run sequence input data with measured data originating from an 

 on-board clock, f 1 uxgate updated gyro compass, depth sensor, and run sequence 

 pointer, respectively. The microprocessor generates digital 8-bit error sig- 

 nals between the programmed values and the measured values, and issues 8-bit 

 error signals to the appropriate linear motor controllers according to a 

 linear control algorithm. The motor controllers then power the pressure com- 

 pensated, 1/4-horsepower, 24-V PC motors which directly drive the propellers. 



Primary power is supplied to the vehicle by a series of 2-V, 25-A-hr, 

 Gates rechargeable lead-acid batteries located in the two long containers 

 mounted beneath the vehicle. These provide 26 and 14 V DC which drive the 

 +5-V and +15-V inverter power supplies and the appropriate regulators to run 

 the other electronics. The present battery pack weighs about 77 lb. Although 

 this pack could be replaced with lithium cells having the same approximate 

 volume but with about five times the energy, they would be nonrechargeable 

 primary cells and would be relatively expensive to replace. 



Software Structure 



The basis of the NOSC free-swimmer control system is the software program 

 presently stored as firmware in 6 kilobytes of programmable read-only memory 

 (PROM), 2 kilobytes of random access memory (RAM) in the vehicle microproces- 

 sor, and 24 kilobytes of RAM in the console microprocessor memory. A brief 

 summary of the software characteristics has been included in table 2. Origi- 

 nally, the software was programmed in 8080 assembly language. When PL/M was 

 made available by INTEL, Inc., it was adapted as the primary programming 

 language for the submersible. PL/M is a microprocessor compatible subset of 

 the PL-1 high-level programming language. It is a modular-structured, high- 

 level compiler which allows a high degree of flexibility for modifying and 

 adding to the scope of the free-swimmer software with a minimum of software 

 development cost. Figure 10 depicts the system's distributed or two-processor 



24 



