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When using OOK modulation the first two
entries into this table are used (index 0
and index 1).
Since the PATABLE is an 8-byte table, the
table is written and read from the lowest
setting (0) to the highest (7), one byte at a
time. An index counter is used to control the
access
to
the
table.
incremented each time a byte is read or
written to the table, and set to the lowest index
when CSn is high. When the highest value is
reached the counter restarts at 0.
The access to the PATABLE is either single
byte or burst access depending on the burst
bit. When using burst access the index counter
will count up; when reaching 7 the counter will
restart at 0. The R/W bit controls whether the
11 Microcontroller Interface and Pin Configuration
In a typical system, CC2500 will interface to a
microcontroller. This microcontroller must be
able to:
Program CC2500 into different modes
Read and write buffered data
Read back status information via the 4-wire
SPI-bus configuration interface (SI, SO,
SCLK and CSn)
11.1
Configuration Interface
The microcontroller uses four I/O pins for the
SPI configuration interface (SI, SO, SCLK and
CSn). The SPI is described in Section 10 on
page 21.
This
counter
is
Figure 9: Register Access Types
SWRS040C
access is a write access (R/W=0) or a read
access (R/W=1).
If one byte is written to the PATABLE and this
value is to be read out then CSn must be set
high before the read access in order to set the
index counter back to zero.
Note that the content of the PATABLE is lost
when entering the SLEEP state, except for the
first byte (index 0).
See Section 24 on page 46 for output power
programming details.
11.2
General Control and Status Pins
The CC2500 has two dedicated configurable
pins (GDO0 and GDO2) and one shared pin
(GDO1)
that
can
output
information useful for control software. These
pins can be used to generate interrupts on the
MCU. See Section 28 on page 51 for more
details on the signals that can be programmed.
GDO1 is shared with the SO pin in the SPI
interface. The default setting for GDO1/SO is 3-
state output. By selecting any other of the
programming options the GDO1/SO pin will
become a generic pin. When CSn is low, the
pin will always function as a normal SO pin.
In the synchronous and asynchronous serial
modes, the GDO0 pin is used as a serial TX
data input pin while in transmit mode.
CC2500
internal
status
Page 25 of 89
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