ata5279n ATMEL Corporation, ata5279n Datasheet - Page 17

• Manufacturer Part Number: ata5279n
• Description: Antenna Driver For Multiple Antennas
• Manufacturer: ATMEL Corporation

3.9
3.9.1
9125C–RKE–01/09
Control Logic
Modulator Stage
Seamless data processing is an important feature of the command buffer. LF data intended for
the same coil and the same current step can be distributed to several commands without the risk
of having unwanted gaps in the LF telegram. This allows protocols to have any length and is
usable both with the Send LF-data and the Send Carrier command. Refer also to the
3.9.1 “Modulator Stage” on page 17
The internal control logic handles all information coming from the SPI and controls the power
stages. Diagnostic information is also collected and evaluated here.
The modulator stage controls the coil drivers. It gets all necessary information from the com-
mand buffer. That is:
When a modulator operation is started by an SPI command, the data in the buffer is processed
in the order it arrives via SPI, command by command. The time for this data processing depends
on the command itself and, if LF transmissions are involved, the amount and length of the data
bits.
Table 3-3
Table 3-3.
Note:
• Which coil to drive
• Which current to maintain in this coil/which diagnosis switch to close (in diagnosis mode)
• Which baud rate to use for LF data transmission
• What kind of transmission (i.e., data or carrier)
• LF data itself (respectively the on-time when a carrier is to be transmitted)
Select Coil Curr.
Send LF Carrier
Send LF Data
Select Driver
Command
Table 3-3
ing or processing time. This is done simultaneous, so that two commands can be executed
seamlessly.
lists the timings for the driver-related commands.
Execution Durations of Driver-related Commands
lists the duration of command execution for the different commands and not the decod-
N
Dur. [LF per.]
T
2
(32 / 22)
< 1
64
{32 / 22}
for further details.
Comment
During the first 32 periods, the actual driver is stopped in order
to decay any oscillation in the coil. Then the switching itself is
performed and another 32 periods waiting time is started in
order to wait for the new driver to reach its operation point
The switching time of internal references takes less than 1 LF
period. Note that there will always be an interruption in a
telegram if the coil current is changed between two transmission
commands
The duration of this command depends on the selected data
rate (4 kbit/s, i.e. 32 periods/LF bit, or 5.7 kbit/s, i.e.,
22 periods/LF bit) and the amount of nibbles N (2 LF data bits)
to be transmitted
The duration of this command depends on the selected data
rate (see also above) and the carrier duration T
ATA5279N [Preliminary]
Section
17