Memory use, Ram use, Eeprom use – Echelon Neuron C User Manual

Page 186

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174 Memory

Management

Memory Use

This section outlines the amount of memory used by certain elements in your

program. For a description of the actual memory used by your program, see the
link summary.

RAM Use

RAM is used as follows:

code

Size of code (for functions declared with ram keyword)

config_prop 0
cp_family 0
fblock 0

io_changes

3 bytes each (any type)

I/O object

0

msg_tag 0
mtimer

4 bytes each

The following sizes pertain to global and static data as declared in the program
(except for eeprom and config variables). These amounts also apply to network

variables.

char 1

byte

int 1

byte

enum 1

byte

long 2

bytes

structures

Sum of the size of the elements. Each 8 bits (or fraction of

8 bits) of consecutive bitfields uses up a byte. No bitfield

can span a byte boundary. No padding is performed. The
float_type and s32_type extended arithmetic structures

each take 4 bytes.

unions

Size of the largest element

EEPROM Use

Approximately 65 bytes of EEPROM is used for constant system overhead,

although this can vary depending on the firmware version. In addition,
EEPROM or flash memory is used as follows:

• Each domain table entry requires 15 bytes for configurable information,

to define the domain address, subnet number, device number, and
authentication key. A system can have a maximum of two domain table

entries and must have at least one domain table entry. The default is
two domain table entries. See

Domain Table

on page 190.

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