44 lines
1.5 KiB
Arduino
44 lines
1.5 KiB
Arduino
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/*
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This example shows how to use Preferences (nvs) to store a
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structure. Note that the maximum size of a putBytes is 496K
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or 97% of the nvs partition size. nvs has signifcant overhead,
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so should not be used for data that will change often.
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*/
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#include <Preferences.h>
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Preferences prefs;
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typedef struct {
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uint8_t hour;
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uint8_t minute;
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uint8_t setting1;
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uint8_t setting2;
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} schedule_t;
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void setup() {
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Serial.begin(115200);
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prefs.begin("schedule"); // use "schedule" namespace
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uint8_t content[] = {9, 30, 235, 255, 20, 15, 0, 1}; // two entries
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prefs.putBytes("schedule", content, sizeof(content));
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size_t schLen = prefs.getBytesLength("schedule");
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char buffer[schLen]; // prepare a buffer for the data
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prefs.getBytes("schedule", buffer, schLen);
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if (schLen % sizeof(schedule_t)) { // simple check that data fits
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log_e("Data is not correct size!");
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return;
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}
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schedule_t *schedule = (schedule_t *) buffer; // cast the bytes into a struct ptr
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Serial.printf("%02d:%02d %d/%d\n",
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schedule[1].hour, schedule[1].minute,
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schedule[1].setting1, schedule[1].setting2);
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schedule[2] = {8, 30, 20, 21}; // add a third entry (unsafely)
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// force the struct array into a byte array
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prefs.putBytes("schedule", schedule, 3*sizeof(schedule_t));
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schLen = prefs.getBytesLength("schedule");
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char buffer2[schLen];
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prefs.getBytes("schedule", buffer2, schLen);
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for (int x=0; x<schLen; x++) Serial.printf("%02X ", buffer[x]);
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Serial.println();
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}
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void loop() {}
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