CC2400 Chipcon AS, CC2400 Datasheet - Page 20

• Manufacturer Part Number: CC2400
• Description: 2.4 GHz RF Transceiver
• Manufacturer: Chipcon AS

4-wire Serial Configuration Interface
CC2400
SPI-compatible interface (SI, SO, SCLK
and CSn) where
interface is also used as data interface in
the buffered mode (see page 26).
There are 44 16-bit configuration registers,
9 Command Strobe Registers, and one
register to access the FIFO. Each register
has a 7-bit address. The FIFO (32 bytes)
is 8 bits wide. A Read/Write bit indicates a
read or a write operation and makes up
the 8-bit address field together with the 7-
bit address.
Some registers are termed Command
Strobe
Command
sequences
commands can be used to quickly change
from RX mode to TX mode, for example.
A full configuration of
sending 44 data frames of 24 bits each (7
address bits, R/W bit and 16 data bits).
The time needed for a full configuration
depend on the SCLK frequency. With a
SCLK frequency of 20 MHz the full
configuration is done in less than 5 µs.
Setting the device in power down mode
requires addressing one command strobe
register only, and will in this case take less
than 0.4 µs. All registers except the strobe
registers are also readable.
In each write-cycle, 24 bits are sent on the
SI-line. The bit to be sent first is the R/W
bit (0 for write, 1 for read). The next seven
bits are the address-bits (A6:0). A6 is the
MSB (Most Significant Bit) of the address
and is sent first. The 16 data-bits are then
transferred (D15:0). During address and
data transfer the CSn (Chip Select, active
low) must be kept low. See Figure 6.
The timing for the programming is shown
in Figure 6 with reference to Table 3. The
clocking of the data on SI into the
is done on the positive edge of SCLK.
Chipcon AS
is configured via a simple 4-wire
Registers.
SmartRF
Strobe
will
CC2400
be
®
CC2400 PRELIMINARY Datasheet (rev. 1.1), 2003-10-02
By
register
is the slave. This
CC2400
started.
addressing
requires
internal
CC2400
These
a
SmartRF
The data word is loaded in the internal
configuration register, when the last bit,
D0, of the 16 data-bits has been written.
The configuration data will be retained
during a programmed power-down mode,
but not when the power-supply is turned
off. The registers can be programmed in
any order.
The configuration registers can also be
read by the microcontroller via the same
configuration interface. The R/W bit must
be set high to initiate the data read-back,
then the seven address bits are sent.
CC2400
addressed register. SO is used as the
data output and must be configured as an
input by the microcontroller.
The command strobe register is accessed
in the same way as for a write operation,
but no data is transferred. That is, only the
R/W bit and the seven address bits are
written before CSn should be set high.
Figure 7 shows a summary of read and
write operations. A register read/write can
be terminated after one byte if only the
MSByte is required. A register can also be
accessed repeatedly without writing the
address again. The buffer FIFO (8 bit
wide,
continuously by simply writing new bytes
over and over. The internal data pointer is
then updated for every written byte. The
session is terminated when the CSn is set
high.
During the transfer of the address, the
CC2400
line containing some important flags. This
is shown in Table 4.
returns a status byte on the SO
32
then returns the data from the
bytes)
®
can
CC2400
be
Page 20 of 73
written