Difference between revisions of "High resolution barometric pressure sensor"
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== LCD interface == | == LCD interface == | ||
| + | The timing is very important, use the hardware timer to make sure the delays are correct. If you use the 4 bit databus you need to read both nibbles, if not you may get the wrong value the next time. | ||
== I<sup>2</sup>C bus == | == I<sup>2</sup>C bus == | ||
| + | Remember the pull-ups on both the clock and data line. First read the 24C02 EEPROM datasheet and the UM10161 - LPC2101/02/03 User manual carefully. Then read the HP03D datasheet. Clock the bus slowly in the beginning to reduce the chance of any problems. | ||
== Parts used == | == Parts used == | ||
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* Supply current 500 uA during A/D conversion | * Supply current 500 uA during A/D conversion | ||
| + | == Controller connections == | ||
| + | LCD Direction LPC2103 Signal | ||
| + | EN <--- P0.17 Enable (10 kOhm pull-up to 5 V on controller) | ||
| + | RW <--- P0.18 Direction of data bus | ||
| + | RS <--- P0.19 Data/instruction select | ||
| + | D4 <--> P0.20 Data 0 | ||
| + | D5 <--> P0.21 Data 1 | ||
| + | D6 <--> P0.22 Data 2 | ||
| + | D7 <--> P0.23 Data 3 | ||
| + | |||
| + | HP03D Direction LPC2103 Signal | ||
| + | 1 - VSS - GND | ||
| + | 2 - VDD - +3.3 V | ||
| + | 3 - MCLK <--- P0.7 - MAT2.0 32768 Hz | ||
| + | 4 - XCLR <--- P0.4 - PIO Reset (Active low, high during A/D operation) | ||
| + | 5 - SDA <--> P0.3 - SDA0 I2C data (10 kOhm pull-up to 3.3 V) | ||
| + | 6 - SCLK <--- P0.2 - SCL0 I2C clock (10 kOhm pull-up to 3.3 V) | ||
| + | |||
[[Category:Electronics]] | [[Category:Electronics]] | ||
Revision as of 23:11, 30 March 2009
Contents
LCD interface
The timing is very important, use the hardware timer to make sure the delays are correct. If you use the 4 bit databus you need to read both nibbles, if not you may get the wrong value the next time.
I2C bus
Remember the pull-ups on both the clock and data line. First read the 24C02 EEPROM datasheet and the UM10161 - LPC2101/02/03 User manual carefully. Then read the HP03D datasheet. Clock the bus slowly in the beginning to reduce the chance of any problems.
Parts used
Suitable parts can be found at Futurlec
ET-BASE ARM2103 controller
- CPU NXP LPC2103
- RAM 8192 bytes
- FLASH 32768 bytes
- Clock rate 59 MHz
- Supply voltage 5 V
LCD display Optrex 20434
- 20 x 4 characters
- 4 bit bus
- Supply voltage 5 V
- Supply current 3 mA
Pressure sensor HP03D
- Pressure range 300-1100 hPa
- 16 bit A/D
- I2C Serial interface
- Accurate to 0.5 hPa
- Supply voltage: 2.2 - 3.6 V (provided by controller)
- Supply current 500 uA during A/D conversion
Controller connections
LCD Direction LPC2103 Signal EN <--- P0.17 Enable (10 kOhm pull-up to 5 V on controller) RW <--- P0.18 Direction of data bus RS <--- P0.19 Data/instruction select D4 <--> P0.20 Data 0 D5 <--> P0.21 Data 1 D6 <--> P0.22 Data 2 D7 <--> P0.23 Data 3
HP03D Direction LPC2103 Signal 1 - VSS - GND 2 - VDD - +3.3 V 3 - MCLK <--- P0.7 - MAT2.0 32768 Hz 4 - XCLR <--- P0.4 - PIO Reset (Active low, high during A/D operation) 5 - SDA <--> P0.3 - SDA0 I2C data (10 kOhm pull-up to 3.3 V) 6 - SCLK <--- P0.2 - SCL0 I2C clock (10 kOhm pull-up to 3.3 V)
