ATAB8402 Atmel, ATAB8402 Datasheet - Page 10

• Manufacturer Part Number: ATAB8402
• Description: BOARD DEMO 433MHZ RF TRANSMITTER
• Manufacturer: Atmel
• Type: Transmitterr

Specifications of ATAB8402

• Frequency: 433MHz
• Wireless Frequency: 315 MHz
• Modulation: ASK, FSK
• For Use With/related Products: ATA8402
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

3. The Demo Board
3.1
3.1.1
3.1.2
10
Peripheral Interfaces
ATA8401/ATA8402/ATA8403
Clock Output
Port Configuration of the Microprocessor
The transmitter provides a clock signal with a crystal accuracy, which can be used as reference
for an external microprocessor. The frequency of the clock signal is:
The clock output signal is CMOS-compatible if the load capacitance on the pin CLK (pin 1) is
lower than 10 pF. Hence, the trace connecting the pin CLK and the microprocessor port must be
as short as possible.
Atmel’s microprocessors M44C090, M44C890, and T48C893 have a special feature to take over
an external clock signal. In real applications with the Atmel’s transmitters, the microprocessor
starts with a RC oscillator to switch the transmitter. After the clock signal has stabilized, the
microprocessor takes over the clock signal as reference. The demo board ATAB8401,
ATAB8402, and ATAB8403 use Atmel’s microprocessor T48C893
The transmitter pins EN and PA_EN must be connected to the CMOS-compatible output stage.
To ensure that the transmitter is in power-down mode during the microprocessor reset, a
pull-down resistor must be applied. For the switches on the demo board, a pull-up resistor is
needed.
With FSK modulation, the modulating port of the microprocessor must be properly defined. The
on resistance of the port must be very small so that the maximum series resonance of the crystal
circuit does not exceed the defined value. Either a pull-up or pull-down resistor is needed for this
port. The port must be set in an open-drain high-current configuration.
Table 3-1.
f
CLK
=
BP40/SC/INT3
BP43/SD/INT3
f
---------- -
BP50/INT6
BP53/INT1
BP20/NTE
256
BP42/T2O
BP60/T3O
XTO
BP21
BP23
Port
Port Configuration of T48C893 on the Demo Board
Equation 17
Pin EN of the transmitter
Switch S3/programming
FSK modulation switch/
Pin PA_EN of the
Programming
Programming
programming
transmitter
Switch S2
Switch S1
Function
LED D1
Output Driver
Open drain
CMOS
CMOS
CMOS
CMOS
CMOS
CMOS
CMOS
CMOS
Pull-up/Pull-down
Pull-down
Pull-down
Pull-down
Pull-down
Pull-down
Resistor
9115A–INDCO–01/08
Pull-up
Pull-up
Pull-up
None