APGRD003 Microchip Technology, APGRD003 Datasheet - Page 22

• Manufacturer Part Number: APGRD003
• Description: KIT TPMS REFERENCE DESIGN
• Manufacturer: Microchip Technology
• Type: Automotive, Tire Pressure Monitorr

Specifications of APGRD003

• Frequency: 433.92MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC18F4680, PIC18F2680, MCP2030
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

DS51624B-page 18
3.4.3.4
The transmitted message follows the HCS365 PWM format via a 433 MHz carrier
signal, which consists of:
• A preamble (31 TE, 50% duty cycle) for baud rate calculation on the receive side
• A header (4 or 10 Te, user selectable)
• Data bytes:
Refer to the HCS365 data sheet (DS41109) for more information.
FIGURE 3-4:
3.4.3.5
• Drive pin RC0 and RA1 high to power up the sensor and the Op-Amp (MCP6273)
• Enable the Op-Amp with pin RA5
• Pin RC2 is set up as the analog input to the internal ADC for pressure measure-
3.4.3.6
• Drive pin RC0 pin high to power up the sensor and the op-amp used for signal
• Pin RC0 is configured as the analog input of the internal ADC. Vref for the ADC is
• The recommended serial resistor (R5) value should be 10 kOhm or greater to
- Tire Location ID (1 Byte, user defined)
- Sensor ID (2 Bytes, user defined)
- Pressure Data (2 Bytes)
- Temperature Data (2 Bytes)
- Battery Low Flag (1 Bit)
- Dummy Bits (7 Bits)
that is used for signal amplification
ment
amplification. This also pulls the sensor bridge high through R5. The R5 and the
sensor bridge form a resistive divider which is monitored by the internal ADC
through pin RA1. Since the sensor internal bridge resistance is temperature
dependent, the voltage on the resistor divider will change accordingly.
selected as internal which is equal to the battery voltage minus the diode drop.
minimize the influence of the parasitic of the microcontroller pins (about
200 Ohm).
Note:
1
Transmission Direction LSb First
RF MESSAGE OVERVIEW
TEMPERATURE MEASUREMENT
PRESSURE MEASUREMENT
For the next three sections, refer to A.13 Circuit Block Figure in
Appendix A. “Schematic and Layouts” for circuit block diagram.
31xTe 50% Preamble
RF MESSAGE FORMAT
16
Header
4-10
xT
E
Data Bytes
LOGIC "0"
LOGIC "1"
© 2006 Microchip Technology Inc.
T
E
T
T
BP
E
T
E