ATA5279-PLQW Atmel, ATA5279-PLQW Datasheet - Page 24

• Manufacturer Part Number: ATA5279-PLQW
• Description: RF Wireless Misc High-end multiple antenna driver IC
• Manufacturer: Atmel

Specifications of ATA5279-PLQW

• Package / Case: VQFN-48
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

24
Atmel ATA5279
Figure 3-15. LF Data Processing
SPi Data String (hex)
• Send LF Carrier:
SPi Data String (bin)
It is important that the amount of nibbles passed in the header word matches the number of
words transferred afterwards to the IC, as no data consistency checking can be carried out
here. If an odd number of nibbles is to be transferred, the data word on the SPI has to be
completed with dummy data in the upper nibble, as the SPI always requires complete data
words on the bus. The FIFO buffer is also only filled with complete words.
For an example, if seven nibbles of LF data (i.e., 14LF data bits) are to be sent by the
Atmel
the header word (here 06h) and four LF data words, whereas the last word contains only
four bits (the four least significant) of the LF data.
For an additional example, see
processed in ATA5279.
This command should be used when a carrier shall be transmitted on the LF channel via
the selected coil. The current will be regulated by ATA5279 to the value selected with the
last Select Coil Current command (resp. the default value of 50mA). See also
“Coil Current Sensing (Zero Cross, Sample and Hold, Integrator)” on page 7
details.
The duration of this carrier can be defined by the T
one LF data bit, i.e., 32LF periods in normal- and 22LF periods in high-speed mode. That
leads to a maximum definable carrier time per command of 31
using an 8MHz system clock.
However, when the T
selected current on the actually active coil is started. This can be used for long-term
measurements or for energy-coupling purposes. Be aware that long-term transmissions
can produce a huge amount of heat in the driver, dependant on the selected coil current
and the properties of the coil itself. It is therefore strongly recommended to use this feature
only with a maximum current settings of 100mA; otherwise, the chip temperature might
reach excessive values.
MACT Signal
BCNT Signal
LF Telegram
®
ATA5279 via the LF channel, the Send LF Data command consists of five words,
0000 0010
4..0
02h
-value is set to 0, an endless carrier transmission with the actually
Figure
3-15, which illustrates how LF transmission data is
0
0
1
35h
1
0
1
4..0
0
1
bits. Note that the time unit here is
0.256ms = 7.936ms when
for further
9125L–RKE–03/11
Section 3.5
0
04h
1
0
0