Barometer Pressure Module HOPE HP03
I 'm after some advice on wiring up the HP03 chip.
The device has 6 pins:
1. Vss
2. Vdd
3. MCLK. Master clock input, 32768Hz
4. XCLR. ADC re-set
5. SDA. IIC comms, data
6. SCL. IIC comms, clock
First question - the wiring diagram in the spec sheet shows the device connected to a MCU with a 32768Hz Xtal i.e. both the MCU and the HP03 share the same clock frequency. Is this necessary? Or, can the MCU run at, say 20MHz and the 32768Hz be provided to the device from another source?
Second Question - Vdd is specified as 2.2 - 3.6 Volts. Vdd Absolute max is 4 Volts. The ratings for the other pins are not given in the spec sheet. Are they '5 Volt tolerant' ?
Regards Bill Legge
5 V to 3v3 with Intersema sensors
I have used hundreds of intersema sensors for atmospheric pressure and 5 - 10 atmosphere applications over the last 5 years. I use a simple resistive divider for the 5>3v3 level conversion. In the 3v3>5 direction I just directly connect.
I run the PIC at 5 volts and the Intersems 5534 at 3v3 from an LDO 3 volt regulator. From PIC to 5534 I have 2k2 with 3k3 to ground at the 5534 end for signals to the 5534 DIn, SClk and MClk. DOut, from the 5534, I just hook directly to the PIC. Yes that means a 3v3 signal into a 5 volt PIC (RC.3). It works.
The HOPE is definitely a knock off of the Intersema product. Has anyone done any side by side accuracy tests? Pricing looks slightly in favour of the HOPE unit but I'm not going to make the change unless the accuracy is at least as good as the Swiss Intersema units.
Cheers
BrianT