problem in propeller 1 code please help

rob26

Hi , i made a simple program, read pressure and temperature values from a HoneyWell pressure sensor type SSCMANV030PA2A3. A Servo puls is generated via de Servo32v9 object.
In the PUB the Servo.Set(Servo_1,1500), is set the servo and works well. But after a delay time in the main loop, Servo.set(Servo_1,1500) is called again, the Sensor data becomes zero. Before that the values are good. The HoneyWell sensor works well on an other propeller 1. The combination of both, Sensor and Servo output, on one propeller 1 is new. The Main program is ServoB_X AD contr v0.01.spin
I have done several tests and combinations but cannot find out what the problem/error is

Is there anyone who sees what might be causing this error?

avsa242

@rob26,

I doubt this is the cause, but in Get_Depth_TempI2C(), there are these three lines:

        data:=I2CPressSens.Read(i2cSCL,ACK)               '2e read
        if data <> 225
            databyte[1] := data

In the other three surrounding if blocks, data is compared to 255, not 225 (I'm guessing 255/$ff signifies data not ready or invalid data from the sensor). Was this supposed to be 255 also?

Also, I haven't yet found the configuration/programming info for this chip, but I don't see where you tell the sensor which register you want to read. In Get_Depth_TempI2C(), you read from the sensor, but I couldn't find where you tell it which register to read from (this could just be my ignorance - maybe it isn't necessary with this sensor).
I find with most sensors (or other I2C devices), you usually have to do something like this to read data from them:

i2c.start()
i2c.write(SLAVE_ADDRESS | 0)
i2c.write(SENSOR_REGISTER)    ' tell the sensor: I'm interested in the data in this register
i2c.stop()

i2c.start()
i2c.write(SLAVE_ADDRESS | 1)
i2c.read(i2c.ACK)
...
i2c.stop()

Cheers

Rayman

Does it work if you comment out the servo.set lines?

rob26

@avsa242,
Thank you for your reaction.
The 225 is a typo, it should also be 255. If have changed it, but the result is the same.

The Address of the sensor is PressSensorAddr = %0101_0000, see CON
The I2C commands such as read and write to the sensor are in the Basic_I2C_Driver.
I have had this Pressure sensor part working for years, but not in combination with the
Servo32v9 software. And i have also been using the Servo32v9 for a while now.
I'm not an expert in making drivers, this was working quickly, so there was no need toe change it.

first step:

• ackbit := I2CPressSens.write(i2cSCL,PressSensorAddr + %0000_0001)
  than 4 bytes to read

• data:=I2CPressSens.Read(i2cSCL,ACK)

@Rayman,
Thanks also, yes, when i comment the { Servo.Set(Servo_1,1500) } in the repeat loop, the data of the pressure sensor stays good

attached the I2C communication protocol for the Honeywell sensor

Rayman

That is odd. Wonder is it’s some timing thing….

Try replacing servo.set with a waitcnt maybe to see if that breaks it too.

avsa242

Maybe a power or noise issue too. Are the servos powered from the same power supply as the Propeller? If possible, you could try to connect them to a separate supply to see if that helps.

rob26

@Rayman,
I have placed waitcnt before and after, no difference.

@avsa242, i use different power supplies, but even without connected the power supply for the Servo. the problem is still there.

the funny thing is that the Servo.Set() in the initAll, is not a problem, but after the delay in the main repeat the data of the pressure sensor stops

very strange problem!