42 lines
1.7 KiB
Markdown
42 lines
1.7 KiB
Markdown
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RAM requirements
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=======
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#### **NeoGPS** requires **72% to 96% _less_ RAM, saving 140 to 1100 bytes.**
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Because you can select what data members are stored, the RAM savings depends on the [configuration](Configurations.md):
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<table>
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<tr><td>Configuration</td><td>NeoGPS<br>Size</td><td>TinyGPS<br>Size (% smaller)</td><td>TinyGPS++<br>Size (% smaller)</td><td>Adafruit_GPS<br>Size (% smaller)</td></tr>
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<tr><td>Minimal</td><td>10</td><td>- (95%)</td><td>- (96%)</td></tr>
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<tr><td>DTL</td><td>25</td><td>- (86%)</td><td>- (90%)</td></tr>
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<tr><td>Nominal</td><td>41</td><td>180 (72%)</td><td>240 (83%)</td><td>326 (87%)</td></tr>
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<tr><td>Full</td><td>242</td><td>- (-)</td><td>~1400 (83%)</td></tr>
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</table>
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#### Why does **NeoGPS** use less RAM?
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As data is received from the device, various portions of a `fix` are
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modified. In fact, _**no buffering RAM is required**_. Each character
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affects the internal state machine and may also contribute to a data member
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(e.g., latitude).
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If your application only requires an accurate one pulse-per-second, you
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can configure it to parse *no* sentence types and retain *no* data members.
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This is the **Minimal** configuration. Although the
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`fix().status` can be checked, no valid flags are available. Even
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though no sentences are parsed and no data members are stored, the
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application will still receive an empty `fix` once per second:
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```
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while (gps.available( gpsPort )) {
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gps_fix nothingButStatus = gps.read();
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sentenceReceived();
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}
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```
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The `ubloxNMEA` derived class doesn't use any extra bytes of RAM.
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The `ubloxGPS` derived class adds 20 bytes to handle the more-complicated protocol,
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plus 5 static bytes for converting GPS time and Time Of Week to UTC.
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