Hope RF
HP01-TQ
BAROMETER MODULE
2010-6-3
PRELIMINARY
Version: 2.1
P2=39/27=1.44
P=1013.2+1.44=1014.6
Serial Interface
The I
2
C interface is used for reading measurement result from AD conversion:D1 and D2.
Reading Temperature and Pressure value:D1,D2
AD chip I
2
C 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:
S 11101110
A
11111111
A
11110000
A
P D S 11101110
A
11111101
A
S 11101111
A
MSB
A
LSB
N P
Select pressure measurement
Temperature Measure:
Read AD value back
S 11101110
A
11111111
A
11101000
A
P D S 11101110
A
11111101
A
S 11101111
A
MSB
A
LSB
N P
Select temperature measurement
Read AD value back
S: I
2
C bus START (refer to AT24C02 EEPROM start command)
P: I
2
C bus STOP (refer to AT24C02 EEPROM stop command)
A (bold):
I
2
C bus acknowledge by slave (SDA pull low: slave send out bit 0)
A: I
2
C bus acknowledge by master (SDA pull low: master send out bit 0)
N: I
2
C 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 [ Hope Microelectronics co., Ltd ]
