Echelon Neuron C - Manual (Page 211)

Neuron C Programmer’s Guide 199
unsigned short int controlReg2;
unsigned long int dataReg;
} *PMemMapDev;
const PMemMapDev pDevice = (PMemMapDev) 0x8800;
void read() {
// Read from device ...
unsigned int x, y;
unsigned long z;
x = pDevice->controlReg1;
y = pDevice->controlReg2;
z = pDevice->dataReg;
}
void write() {
// Write to device ...
unsigned int x, y;
unsigned long z;
pDevice->controlReg1 = x;
pDevice->controlReg2 = y;
pDevice->dataReg = z;
}
What to Try When a Program Does Not Fit on a
Neuron Chip
The following discussion contains tips and techniques for reducing the EEPROM
requirements of a program for purposes of getting it to fit or having it use less
code space. Some of the techniques are tailored to a Neuron 3120 Chip or FT
3120 Smart Transceiver, but most are applicable to any Neuron C language
program. Most of these manual optimization techniques improve both aspects of
code size and code performance. The techniques below should be attempted
roughly in the order presented.
While the memory map for a Series 3100 device is usually fixed and defined by
hardware, some out-of-memory link-time errors for a Series 5000 chip can be
addressed by adjusting the memory map according to the application’s needs.
Although you cannot define the memory map to exceed the FT 5000 Smart
Transceiver’s or Neuron 5000 Processor’s inherent limits, you can increase or
decrease the amount of RAM available (at the expense of EEPROM or flash
memory available) in steps of 256 bytes.
Many of the suggestions presented in the sections that follow lead not only to
smaller code or data (to better fit the target device), but also lead to faster, more
efficient, code. It is, therefore, recommended that you familiarize yourself with
the all of the following recommendations, regardless of your preferred target
Neuron Chip or Smart Transceiver model.
The link map contains information about a program’s current memory usage.
The summary information includes an estimate of the additional memory
required. The link summary is optionally output to the BUILD.LOG file, and is