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Make sure conversion is complete; fix ads1015 scaling. #174

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Make sure conversion is complete; fix ads1015 scaling. #174

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359faea
Make sure conversion is complete; fix ads1015 scaling.
fovea1959 Jun 24, 2023
4e77dfe
ads1015 handle negatives, do lazy tracing.
fovea1959 Jun 24, 2023
22b8bb1
I didn't know tinylog had a .isTraceEnabled(). Use that.
fovea1959 Jul 13, 2023
7013b05
Remove bad attempts at optimization.
fovea1959 Jul 15, 2023
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49 changes: 40 additions & 9 deletions diozero-core/src/main/java/com/diozero/devices/Ads1x15.java
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Original file line number Diff line number Diff line change
Expand Up @@ -314,6 +314,9 @@ public byte getMask() {
private DigitalInputDevice readyPin;
private float lastResult;

// for tracing
private boolean amTracing = false;

/**
*
* @param pgaConfig Programmable Gain Amplifier configuration - make sure this
Expand Down Expand Up @@ -353,6 +356,8 @@ private Ads1x15(int controller, Model model, Address address, PgaConfig pgaConfi
boardPinInfo = new Ads1x15BoardPinInfo(model, pgaConfig.getVoltage());
device = I2CDevice.builder(address.getValue()).setController(controller).setByteOrder(ByteOrder.BIG_ENDIAN)
.build();

amTracing = Logger.isTraceEnabled();
}

@Override
Expand Down Expand Up @@ -464,20 +469,48 @@ private void setDataRate(int dataRate, byte dataRateMask) {
this.dataRateMask = dataRateMask;
}

public void waitUntilReady() {
long t0 = 0;

if (amTracing) { // only want to hit currentTimeMillis() if necessary
Logger.trace("waitUntilReady hit");
t0 = System.currentTimeMillis();
}

SleepUtil.sleepMillis(dataRateSleepMillis);
int incrementalSleepMillis = Math.max(dataRateSleepMillis / 20, 1);

int i = 0;
while (true) {
short data = device.readShort(ADDR_POINTER_CONFIG);
if ((data & 0x8000) != 0) break;
SleepUtil.sleepMillis(incrementalSleepMillis);
i++;
}

if (amTracing) {
long t1 = System.currentTimeMillis();
Logger.trace("waitUntilReady done, took {} ms, {} iterations", t1 - t0, i);
}
}

public float getValue(int adcNumber) {
Logger.debug("Reading channel {}, mode={}", Integer.valueOf(adcNumber), mode);
Logger.debug("Reading channel {}, mode={}", adcNumber, mode);

// TODO Protect against concurrent reads

if (mode == Mode.SINGLE) {
setConfig(adcNumber);

SleepUtil.sleepMillis(dataRateSleepMillis);
waitUntilReady();
} else if (readyPin != null) {
return lastResult;
}

return RangeUtil.map(readConversionData(adcNumber), 0, Short.MAX_VALUE, 0, 1f);
short conversionData = readConversionData(adcNumber);
// need to set constrain to false: we *could* get a negative if doing differential
float rv = RangeUtil.map(conversionData, 0, 0x8000, 0, 1f, false);
Logger.trace ("mapped {} to {}", conversionData, rv);
return rv;
}

protected void setConfig(int adcNumber) {
Expand All @@ -486,18 +519,16 @@ protected void setConfig(int adcNumber) {
byte config_lsb = (byte) (dataRateMask | comparatorMode.getMask() | comparatorPolarity.getMask()
| (latchingComparator ? CONFIG_LSB_COMP_LATCHING : 0) | comparatorQueue.getMask());
device.writeI2CBlockData(ADDR_POINTER_CONFIG, config_msb, config_lsb);
Logger.trace("msb: 0x{}, lsb: 0x{}", Integer.toHexString(config_msb & 0xff),
Integer.toHexString(config_lsb & 0xff));
Logger.trace("setConfig: 0x{} 0x{}", Integer.toHexString(config_msb & 0xff),
Integer.toHexString(config_lsb & 0xff));
}

private short readConversionData(int adcNumber) {
// byte[] data = device.readI2CBlockDataByteArray(ADDR_POINTER_CONV, 2);
// short value = (short) ((data[0] & 0xff) << 8 | (data[1] & 0xff));
short value = device.readShort(ADDR_POINTER_CONV);

if (model == Model.ADS1015) {
value >>= 4;
}
Logger.trace("readConversionData: 0x{}, {} dec", Integer.toHexString(value), value);

return value;
}
Expand Down