Remote-processing RPC-2350 Manuel d'utilisateur télécharger pdf (Page 30)

DATA MEMORY CHAPTER 5

5-4

structure it is 28.

Next, assign variable names to the offsets in memory

data begins.

Name Pointing to Value

DSET Date string 0

TSET Time string 9

TPSET Temperature 18

PSET Tick time 22

LSET Level 26

This is simply done by making a variable equal to a

number. F or example,

PSET = 22

NOTE: The word “ SET” does not have any

significance other than naming the variable.

You will need a pointer to track the n umber of data sets

(structur es) saved. You will also have to chec k this

pointer to make sure you are not exceeding the

maximum amount of memory. Use one of the protected

variables (A%-Z% ) as the pointer. This way, if power

disappears, the pointer is still in tact. Protected

variables can also be used to keep track of the segment

used to store data in.

A sample C AMBASIC line to store data is:

FPOKE A%*28TPSET,value,B%

This example uses A% as the pointer and B% to track

the segment number. ‘TPSET’ and B% could just as

easily be constants.

This structure will save 2340 elements in 64K of RAM.

Therefore, you should test A% for a limit of 2340 once

each loop.

A 512K RAM can store up to 7 segments. Therefore,

B% is checked fo r a value o f 8 or m ore at the end of this

loop.

If your data requirements are more than available RAM,

you can stor e some in F lash. You will ha ve to first w rite

the data to RAM first, then save to flash.

Flash is also used to save critical information. However,

Flash will “ wear out” after 1, 000 to 10,000 writes.

You will probably have to make an initial guess at your

program size. As a practical fact, no m ore than about

34K of program can run at one time. This leaves about

30K in the first Flash segment and at least this amount in

the 2nd. Use the SA VE command to transfer data to

Flash.

You can start saving at address &8400 and not interfere

with the first program. If you SAVE to segment 9 and

are using graphics on the RPC-2350G, larger fonts are

stored starting at address &AC00. Put a limit check at

this address. W hen a 512K F lash is installed, segments

2-7 are available, if there are no other programs in them.

The SYS(0) function returns your progr am size. Y ou

can use this figure to determine where you can start

saving in Flash. Be sure to round up to the next page

boundary (last two bytes of the address) to &00 when

determ ining your data start of a ddress. This is to

account for the Flash block size.

All cases limit maximum address to &F FFF in any one

segment. Be sur e to read “ Considerations for saving to

Flash” below for more inform ation.

Since each situation is unique, call Remote Pr ocessing

technical support at 303 690 1588 to discuss your

problem further.

Considerations f or saving to Flash

The RPC-2350G uses &5A00 bytes in the Flash EPROM

to store gr aphics fonts. The fonts a re stor ed starting in

segment 9, address & AC0 0. T his is high enough in

memory so no CAM BASIC program will interfere with

it. Only if you use medium and large size fonts on the

RPC-2350G will you have to consider this as an upper

memory limit for storing data. Consider installing a

512K byte flash and saving to segments 2-7.

Flash EPROM is written to in blocks, or sectors of 128

(29C010A installed) or 256 (29C040A installed) bytes

each. This means if you want to save just 1 byte, 128 or

256 bytes are used. You must pay attention to sector

size for two reasons. F irst, a sector is the minimum

number of bytes written. If a program requires only 35

bytes to be saved, a full sector is written. If you had the

following in your code:

1000 SAVE 1,5,1,&1000,35

2000 SAVE 1,42,1,&1025,35

1 2 ... 25 26 27 28 29 30 31 32 33 34 35 ... 82 83

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Remote-processing RPC-2350 Manuel d'utilisateur Page 30

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