MRF24J40 Datasheet, PDF (16/66 Pages) Microchip Technology – IEEE 802.15.4™ 2.4 GHz RF Transceiver

MRF24J40
4.2 Short Address Register Interface
4.2.1
READING SHORT ADDRESS
REGISTERS
The short address space is accessed by sending a ‘0’
as the first bit of the SPI transfer. The following 6 bits
are the address of the target register. The final bit of the
first byte is a ‘0‘ to indicate that the command is a read.
On the next clock edge of SCK, the Most Significant bit
of the register will shift out, followed by the rest of the
bits.
FIGURE 4-3:
SHORT ADDRESS READ
CS
SCK
SDI 0
A5 A4 A3 A2 A1 A0
0
X
SDO
D7 D6 D5 D4 D3 D2 D1 D0
EXAMPLE 4-1: SHORT ADDRESS READ EXAMPLE
BYTE GetShortRAMAddress(BYTE address)
{
BYTE toReturn;
CSn = 0;
SPIPut((address<<1)&0b01111110);
toReturn = SPIGet();
CSn = 1;
return toReturn;
}
DS39776A-page 14
Advance Information
© 2006 Microchip Technology Inc.