Remote-processing RPC-2350 Manual do Utilizador descarregar pdf (Página 27)

CHAPTER 5 DATA MEMORY

5-1

Figure 5-1 Memory location

CHAPTER SYNOPSIS

 Battery backup description

 Where and how to store variables

 Saving and retrieving data from F lash

 Installing 512K RAM

 Discussion about corrupted da ta

DESCRIPTION

DATA MEMORY CHAPTER 5

The RP C-2350 is usually installed w ith 128K of RA M in

socket U2. A n optional 512K can be installed. RAM is

battery backed on both models.

This chapter discusses saving and retrieving variables

from RAM and Flash EPROM and running assembly

language progr ams.

If program and data are battery backed, the UNNEW

command may be used to try to restore the program.

Variables used by the Basic program are cleared,

however. Certain variab les are pr eserved and data

POKEd into RAM is saved.

BATTERY BACKUP

Battery life is about 3 years (27,000 hours). See

additional information a few paragraphs below.

Battery B1 is used to back up the RAM and real time

clock

The installed battery is rated for 190 mA-hours. RAM

(any size) typically requires 1-2 micro-amps in standby.

The clock requires typically 3 micro-amps. Assuming 7

micro-Amps of current draw, you could expect 3 years

life from the battery (assuming the board was off the

whole time.)

The problem with calculating battery life are variables

beyond our reasonable control. First, memory

manufacturers specify a ‘typical’ current of 1 to 2 micro-

amps and a maximum of 100 (high temperature

operation). Other factors affecting battery life include

operating temperature, clock chip, and time the RPC-

2350 has power applied to it. You can expect the battery

to last between 3 to 5 years for operation at 25°C. At

50°C, life is about half as much. This is due to battery

deterioration and CMOS leakage increases at higher

temperatures.

Humidity also affects battery life. Very high humidity

(in conjunction with a dirty environment) increases

leakage. Low humidity drys out the batter y seal,

allowing contaminates to enter.

The point of this explanation is to give you the factors

affecting battery life. Under the best of conditions, life

is 7 years. Under worse conditions, it could be as low

as 3 months. You can add a larger battery as described

below.

Existing battery voltage is measured across W14.

Alternate battery

A larger 3. 0V batter y can be installed by connecting it to

W14. Be sure to remove the existing battery. Note the

polarity marked on the board.

STORING VARIABLES IN RAM

The term "var iables" in this context includes numb ers,

strings, arrays, recipes, and formulas as applied to your

application.

CAMBASIC provides 26 “protected” variables, A%-

Z%, that are not erased on power up. These are

accessed like other BASIC variables.

The Flash EPROM may be used to store variables or

constants, such as text strings, to help reduce the size of

the main program.

CAM BASIC m emory map

The following diagram is a memory map for the RPC-

2350.

1 2 ... 22 23 24 25 26 27 28 29 30 31 32 ... 82 83

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