ESNFAQV1.DOC

Essential Services Node (ESN) Frequently Asked Questions (FAQ)

Version 1 12/9/96

This document will address some of the more frequently asked questions
since the ESN's introduction. The following questions are addressed in
this version of the FAQ:

1\. What is an ESN ?

2\. Where can I get more detailed information ?

3\. What is the physical size and weight of an ESN ?

4\. What is the power dissipation of an ESN ?

5\. What GSFC programs are currently using an ESN ?

6\. What software tools are available for the ESN ?

7\. Where can I get the GSFC written Operating System ?

8\. Where can I get an ESN ?

9\. Where can I buy a board that uses an ESN ?

10\. Who should I contact if I have questions ?

**1. What is an ESN ?**

The Essential Service Node (ESN) is a standard interface device between
a spacecraft instrument or subsystem and the spacecraft's Command and
Data Handling (C&DH) system. The ESN features such hardware as:

> UTMC UT69R000 16-bit processor,
>
> UTMC BCRTM 1553/1773 protocol chip,
>
> 8251 UARTs,
>
> 8255 Parallel Port,
>
> 16-bit serial interface,
>
> various timers,
>
> 192 Kbytes of Static RAM,
>
> and a 12-bit A/D converter

all in a 2.6" x 2.6" x 0.3" Multi-Chip Module (MCM).

The ESN was designed by Bob Caffrey (while in GSFC, Code 735) and Mike
Cuvielo (of Jackson and Tull). The ESN is fabricated by Honeywell CTO in
Phoenix, AZ.

**2. Where can I get more detailed information ?**

The Hardware specification describes the hardware operation, addresses,
pinouts etc. The ESN Hardware Specification can be downloaded from the
ESN website at:

http://code735.gsfc.nasa.gov/phil/current.htm

The latest version of the ESN Hardware Specification is ICD-735-2827 REV
2.0, dated August 16,1996.

**3. What is the physical size and weight of an ESN ?**

The ESN package is 2.6" x 2.6" x 0.3", it is a quad flatpack type
package with 392 leads, 98 on a side. The ESN weighs 95 [+]{.underline}
10 g.

**4. What is the power dissipation of an ESN ?**

The following major modes of operation have been measured at the GSFC
Facility:

Post-Reset Operation, Execution from PROM\'s

[MCM Power Pin Current Power]{.underline}

+5VDC Digital: 86.0 mA 430 mW

+5VDC Analog: 27.0 mA 135 mW

+15VDC Analog: 19.0 mA 285 mW

-15VDC Analog 25.0 mA [375 mW]{.underline}

Total 1.225 W

Analog Power Disabled, Processor Active from PROM\'s:

[MCM Power Pin Current Power]{.underline}

+5VDC Digital: 86.0 mA 430 mW

+5VDC Analog: 0 mA 0 mW

+15VDC Analog: 0 mA 0 mW

-15VDC Analog 0 mA [0 mW]{.underline}

Total 430 mW

Analog Power Disabled, Processor Active from instruction RAM:

[MCM Power Pin Current Power]{.underline}

+5VDC Digital: 100.0 mA 500 mW

+5VDC Analog: 0 mA 0 mW

+15VDC Analog: 0 mA 0 mW

-15VDC Analog 0 mA [0 mW]{.underline}

Total 500 mW

Analog Power Disabled, Processor Active from instruction RAM, Operating
on

Data RAM:

[MCM Power Pin Current Power]{.underline}

+5VDC Digital: 145.0 mA 725 mW

+5VDC Analog: 0 mA 0 mW

+15VDC Analog: 0 mA 0 mW

-15VDC Analog 0 mA [0 mW]{.underline}

Total 725 mW

Analog Power Disabled, Processor Asleep, BCRTM Active:

[MCM Power Pin Current Power]{.underline}

+5VDC Digital: 62.0 mA 310 mW

+5VDC Analog: 0 mA 0 mW

+15VDC Analog: 0 mA 0 mW

-15VDC Analog 0 mA [0 mW]{.underline}

Total 310 mW

**5. What GSFC programs are currently using an ESN ?**

The MIDEX MAP and NMP EO-1 programs are using 4 ESNs in the spacecraft
avionics. In addition, the Fourth Generation TDRSS Transponder will
include an ESN, as well as the Ka-Band Phased Array antenna that has
just been specified.

In the MIDEX MAP and NMP EO-1 programs, the ESN is on a board referred
to as a Remote Services Nodes (RSNs). The five RSNs in the MIDEX MAP
program are the: Tranponder RSN, the Housekeeping RSN, the Attitude
Control Electronics (ACE) RSN, and the Power System Electronics (PSE)
RSN.

**6. What software tools are available for the ESN ?**

[UTMC tool suite]{.underline} (available from UTMC for approx \$3000)

C compiler (GNU) - generates assembly code for the UT69R000 from C, C++,
or Objective C source code. Currently supported on Sun/Solaris Unix
workstations.

Assembler (RASM) - inputs assembler source files, outputs object files.
Operates on both PC and Unix hosts.

Linker (RLNK) - combines object files to and executable Intel Hex file.

Disassembler (RISCIA)

Simulator (IRSIM) - interactive simulator. Permits the development of
code without need for hardware. Allows breakpoints, examination of
memory/registers etc..

IRSIM Monitor - target resident software which communicates with
simulator via an RS-232 link.

[GSFC Developed Tool Suite]{.underline} (free)

C-Compiler (GNU) - input C source files and outputs them in object form.
Has passed 90% of Metaware validation and test suite. Floating point
still has problems.

Macro pre-processor - macro expansion

Assembler - inputs assembler source files, outputs object files.

Linker - combines multiple object files, resolves inter-file symbolic
references and outputs the result in a form that may be either bound
directly to the machine addresses or reprocessed in order to resolve
further symbolic references.

Binder - reads the input file, evaluates all expressions, resolves all
remaining symbol references, binds each section to an address, and
outputs Intel hex files.

Library Management Utility - creates, appends, deletes, replaces
elements in a library

Eeprom - inputs Intel Hex files defining the code and data for an
executable and combines them into a single Intel Hex file used to burn
EERPOMs.

**7. Where can I get the GSFC written Operating System ?**

Contact Ray Whitley, Leader of the Flight Software Group, Code 735 at
(301) 286-6404 or Ray.Whitley@gsfc.nasa.gov

**8. Where can I get an ESN ?**

Contact Ed Roberts of Honeywell (602)0436-2658.

**9. Where can I buy a board that uses an ESN ?**

Two boards are available presently, an ASIC test board and an MCM test
board.

The ASIC test board was used to test the ASIC in the ESN circuit. All
parts except the ASIC are in discrete DIP form.

The MCM Test Board has been designed and has been used to test and
validate the ESNs received. It has the ESN in a fuzz button socket for
ease of removal following testing.

Both boards are available from Jackson and Tull, Contact Bill Dentel at
(301) 8005-6090.

**10. Who should I contact if I have questions ?**

Questions can be addressed to:

Philip.Luers@gsfc.nasa.gov

Mark.Frigaard@gsfc.nasa.gov

Ray.Whitley@gsfc.nasa.gov

or Ed Roberts of Honeywell (602)0436-2658.

End of ESNFAQV1