Will there be paper documentation?

Eventually, yes. Though it will most likely be a purchasable option rather than an integral part of the Persistor package.

Why a 3.3 volt controller?

Power consumption. Almost all of the power used by the CF1's static CMOS componentry comes from switching currents that vary linearly with operating speed, but as the square of the supply voltage. This implies that for any given task, the 3.3V CF1 will consume about half the power, and run twice as long as an equivalent 5 volt controller.

Why no onboard A/D converter?

Which one? Seriously. There exists dozens of A/D device variations because every application demands something different. Instead of sticking in a compromise 12 bit, multichannel chip (though we did that with a RecipeCard), we offer the QPB driver package that lets you quickly add any of these dozens of SPI A/D converters in just about any combination and quantity. We'll even help you setup the parameter tables for the devices you want and publish the interface information for the next developer. The CF1 has so much flash, we may just embed every popular SPI device into the libraries.

Why no onboard switching regulator?

Yes, that could have been nice, but switchers require fairly bulky inductors and they tend to be noisy. Ideally, we would have featured both a linear and switching regulator but there was just not enough room and it certainly would have affected pricing. Also, the onboard linear regulator is particularly accommodating and protective of the CF1 circuitry, and this would be very difficult to give up.

Can I use BDM with the CF1?

Yes, but you must use one designed for 3.3 volt operation, and we do not offer BIOS or technical support for this form of debugging. The block of pins on connector C with the white silk screen correspond to the standard Motorola pinout for Background Debugging Mode and we actually use that at the factory for test and initial configuration. P&E Microcomputer Systems, Inc. sells an inexpensive and low voltage CPU16/32 ICD interface cable called the CAB-3V and you can find them at www.pemicro.com.

Is the BIOS and PicoDOS library source available?

No. These are the proprietary and confidential property of Persistor Instruments Inc.. On a case-by-case basis, and with signed nondisclosure and noncompete agreements, we may on occasion make small portions of specific parts of the library source available to help you in uncovering programming problems that defy normal debugging techniques.

We do make available certain parts of the library source code like the CRC16 and CRC32 functions and tables where the exact functioning must be replicated on another computer to make proper use of the functionality.

Why do strange things happen when I use Windows to delete files?

Windows doesn't necessarily delete files when you drag them into the recycle bin. What actually happens depends on property settings selected for your recycle bin, but by default, Windows marks the file as recycled, then creates a folder named "RECYCLED" on the CompactFlash card, then renames and moves the file(s) into this directory and also creates an index file so you can later change your mind and recover the file(s). Until you empty the recycle bin, none of the space taken by these files is available, and even after you empty, the "RECYCLED" folder remains on the card.

Our strong suggestion is to use PicoDOS on the CF1 to format cards and to perform directory maintenance.

When is it appropriate to use SUSPEND mode?

Strictly in terms of overall power consumption, you need to be in suspend mode for about 20 seconds to make up the difference in energy used by the 300ms wakeup from SUSPEND (about 6mA-s with CF card, 5mA-s without) versus the power you would have drawn by dropping into the deepest LPSTOP mode (about 300uA with CF card, 250uA without). These numbers are based on a CF1 installed in a minimal system like the PRC-PLG which itself adds a 100uF capacitor that has to be charged with each SUSPEND wakeup. You also should consider that your main battery pack probably has a great deal more energy to offer than the button cell that supplies all of the current (approximately 2.5uA) when the CF1 is in SUSPEND.

A good rule-of-thumb would be to restrict SUSPEND to idle intervals of a minute or more.

What is the max throughput for XMODEM and YMODEM at 115,200 BAUD

We get about 9300 bytes per second using YMODEM or XMODEM 1K with Hyperterm and Win98 on a fast Dell box. I'd expect very little variation from the CF1 end, but the actual transfer rate may be affected by the receiving program.

How much static RAM is available for use by the application program?

192KB of heap space for a standard CF1. For programs executing out of RAM, some of that is of course taken for the application code.

Last Update: 98/10/09 

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