Hope RF
HP01-TQ
Version: 2.1
BAROMETER MODULE
2010-6-3
PRELIMINARY
P2=39/27=1.44
P=1013.2+1.44=1014.6
Serial Interface
The I2C interface is used for reading measurement result from AD conversion:D1 and D2.
Reading Temperature and Pressure value:D1,D2
AD chip I2C address is set to 0xEE (device write address), 0xEF (device read
address). In order to get the AD value D1 and D2, you have to follow the following
timing sequence:
Pressure Measure:
A
A
A
A
A
A
S 11101110 11111111 11110000 P D S 11101110 11111101 S 11101111 MSB A LSB N P
Select pressure measurement
Read AD value back
Temperature Measure:
A
A
A
A
A
A
S 11101110 11111111 11101000 P D S 11101110 11111101 S 11101111 MSB A LSB N P
Select temperature measurement
Read AD value back
S: I2C bus START (refer to AT24C02 EEPROM start command)
P: I2C bus STOP (refer to AT24C02 EEPROM stop command)
A (bold): I2C bus acknowledge by slave (SDA pull low: slave send out bit 0)
A: I2C bus acknowledge by master (SDA pull low: master send out bit 0)
N: I2C bus no acknowledge from master (SDA keep high: master send out bit 1 instead)
D : delay for 38ms or above
MSB: conversion result (MSB bit clocked out first)
LSB: conversion result (MSB bit clocked out first).
Remark:
Before start an AD conversion cycle, remember to set XCLR pin high so that the system
is no longer in the reset state (not valid for HP01).
4
HOPERF [ HOPERF ]
