Newsgroups: comp.sys.palmtops
Subject: Re: More Info on A/D Converters for the HP95
From: rrd@hpfcso.FC.HP.COM (Ray Depew)
Date: Fri, 13 Nov 1992 20:50:07 GMT
Organization: Hewlett-Packard, Fort Collins, CO, USA

Also edited from the original.  See the end for additional comments.
-- rrd 921113

-------------------------------------------------------------------
> Hi Ray-
> 
> Thanks for the review.  I was hoping you would supply some of the more
> interesting specs like maximum sample rate, conversion time, and
> sample & hold specifics (impedance, sample time, anti-aliasing
> filters, etc.).  Perhaps these specs are not available in the manual
> (if they aren't they should be!).

Can do.  From the manual, here is the "Specifications" section, followed
by other miscellaneous stuff culled from the pages:

============================================================================
SPECIFICATIONS

Analog Inputs
-------------
Input Configuration:		MOSFET Input Op-Amp Follower

Input Impedance:		1 Megohm for Vin from -.6 to 5.7 volts,
				otherwise 100K ohms

Input Range:			0 to 5.1 volts (0 to 255), 30V maximum

Resolution/Accuracy:		8 bits, 0.4% accuracy +/- .5 LSB

Digital Inputs
--------------
Input Configuration:		74HCT Schmidt Trigger with 100K pullup

Logic High Level:		TTL/CMOS compatible; 2.0 volts minimum

Logic Low Level:		TTL/CMOS compatible; 0.8 volts maximum

Input Current High:		0 uA maximum (floating inputs are high)

Input Current Low:		50 uA (100K pullup)

Maximum Input level:		30 VDC maximum

Digital Outputs
---------------
Output Configuration:		Open drain MOSFET to common

Output Resistance:		1 ohm maximum

Output current:			.5 amps continuous maximum

Output Voltage:			30 volts maximum in off state
				.5 volts maximum in on state

Power
-----
Battery Type:			9V, NEDA 1604 (alkaline) [normal 9V thing - rrd]

Battery Life:			60 hours minimum, continuous operation
				2000 hours typical in standby

Current Drain:			6 mA maximum, .25 mA standby (PWM active)

Physical/Environmental
----------------------
Size:				3-1/4" width by 4-3/8" length by 1-1/2" height

Weight:				6 ounces

Connectors:			Augat RDI 2SV Series-  Lever Action- 
				Wire sizes- #18 to #28 AWG

Temperature Range:		0 to 55 degrees C (32 to 130 degrees F)

============================================================================
MISCELLANEOUS OTHER INFORMATION

Counter/Frequency Input
-----------------------
Maximum Frequency:		100 KHz max

Maximum Count:			16,777,216 (24-bit counter)

Sample Rate:			1 second (fixed)

PWM Output
----------
Frequency:			903.53 Hz

Duty Cycle Range:		0 to 100%

Duty Cycle Resolution:		0.4% or 1/255 (8-bit modulator)

Burst mode analog input
-----------------------
Sample rate:			131 analog samples at .01 seconds per sample

[No data given on normal mode analog input, but I suspect that it also has
a S&H rate of 0.01 second. -- rrd]

======================================================================

ADDITIONAL COMMENTS, 921113:
---------------------------

The ADCM-48 was made to work with the 48, but there's no reason it couldn't
work with the 95.  There is, the small problem of software.  The as-delivered 
HP95 cannot communicate directly with the ADCM.  Anybody want to write a
small program to do the job?  If you are interested, contact John Wettroth
at Travtech -- address and phone number given in my previous postings.

--
Regards
Ray Depew
Hewlett Packard Co, Fort Collins, Colorado
rrd@hpfiqa.fc.hp.com