
CYRF6936
Document #: 38-16015 Rev. *G
Page 5 of 40
Frequency Synthesizer
Before transmission or reception may begin, the frequency
synthesizer must settle. The settling time varies depending on
channel; 25 fast channels are provided with a maximum
settling time of 100
μ
s.
The ‘fast channels’ (less than 100
μ
s settling time) are every
third channel, starting at 0 up to and including 72 (for example,
0, 3, 6, 9….69, 72).
Baseband and Framer
The baseband and framer blocks provide the DSSS encoding
and decoding, SOP generation and reception and CRC16
generation and checking, as well as EOP detection and length
field.
Packet Buffers and Radio Configuration Registers
Packet data and configuration registers are accessed through
the SPI interface. All configuration registers are directly
addressed through the address field in the SPI packet (as in
the CYWUSB6934). Configuration registers allow configu-
ration of DSSS PN codes, data rate, operating mode, interrupt
masks, interrupt status, and so on.
SPI Interface
The CYRF6936 IC has an SPI interface supporting communi-
cations between an application MCU and one or more slave
devices (including the CYRF6936). The SPI interface supports
single-byte and multi-byte serial transfers using either 4-pin or
3-pin interfacing. The SPI communications interface consists
of Slave Select (SS), Serial Clock (SCK), and Master
Out-Slave In (MOSI), Master In-Slave Out (MISO), or Serial
Data (SDAT).
The SPI communications are as follows:
Command Direction (bit 7) = ‘1’ enables SPI write trans-
action. A ‘0’ enables SPI read transactions.
Command Increment (bit 6) = ‘1’ enables SPI auto address
increment. When set, the address field automatically incre-
ments at the end of each data byte in a burst access,
otherwise the same address is accessed.
Six bits of address.
Eight bits of data.
The device receives SCK from an application MCU on the SCK
pin. Data from the application MCU is shifted in on the MOSI
pin. Data to the application MCU is shifted out on the MISO
pin. The active LOW Slave Select (SS) pin must be asserted
to initiate an SPI transfer.
The application MCU can initiate SPI data transfers using a
multi-byte transaction. The first byte is the Command/Address
byte, and the following bytes are the data bytes as shown in
Figure 4
through
Figure 7 on page 6
.
The SPI communications interface has a burst mechanism,
where the first byte can be followed by as many data bytes as
desired. A burst transaction is terminated by deasserting the
slave select (SS = 1).
The SPI communications interface single read and burst read
sequences are shown in
Figure 5
and
Figure 6
, respectively.
The SPI communications interface single write and burst write
sequences are shown in
Figure 7
and
Figure 8
, respectively.
This interface may optionally be operated in a 3-pin mode with
the MISO and MOSI functions combined in a single bidirec-
tional data pin (SDAT). When using 3-pin mode, user firmware
should ensure that the MOSI pin on the MCU is in a high
impedance state except when MOSI is actively transmitting
data.
The device registers may be written to or read from one byte
at a time, or several sequential register locations may be
written/read in a single SPI transaction using incrementing
burst mode. In addition to single byte configuration registers,
the device includes register files; register files are FIFOs
written to and read from using nonincrementing burst SPI
transactions.
The IRQ pin function may optionally be multiplexed onto the
MOSI pin; when this option is enabled the IRQ function is not
available while the SS pin is LOW. When using this configu-
ration, user firmware should ensure that the MOSI pin on the
MCU is in a high impedance state whenever the SS pin is
HIGH.
The SPI interface is not dependent on the internal 12 MHz
clock. Registers may therefore be read from or written to while
the device is in sleep mode, and the 12 MHz oscillator
disabled.
The SPI interface and the IRQ and RST pins have a separate
voltage reference pin (V
IO
), enabling the device to interface
directly to MCUs operating at voltages below the CYRF6936
IC supply voltage.
Table 2. Typical Range Observed Table
Environment
Outdoor
Typical Range (meters)
30
Office
Home
20
15
Note: Range observed with CY4636 WirelessUSB LP KBM v1.0 (Keyboard)
[+] Feedback