BC68FB540 Datasheet, PDF (161/200 Pages) Holtek Semiconductor Inc – I/O Flash USB 8-Bit MCU with 2.4GHz RF Transceiver

BC68FB540
I/O Flash USB 8-Bit MCU with 2.4GHz RF Transceiver
TX Mode
• Primary Transmit Device – PTX, PRIM_RX=0
The TX mode is an active mode where the PTX device transmits a data packet. To enter this
mode from power down mode, the PTX device must set the PWR_UP bit to high, the PRIM_
RX bit to low, a payload in the TX FIFO and generate a high pulse on the CE line for more than
15μs.
The PTX device stays in the TX mode until it finishes transmitting the current packet and then
enters the Standby-II mode. If the CE signal is in a low state, it will return to Standby-I mode.
If the CE signal is in a high state, the next action will be determined by the status of the TX
FIFO. If the TX FIFO is not empty, the PTX device will enter the TX mode and then transmit
the next packet. If the TX FIFO is empty, the PTX device will remain in the Standby-II mode.
It is important to note that it never remains in the TX mode for more than 4ms during a transmit
operation.
If the auto retransmit is enabled by setting the EN_AA bit to 1 and an auto acknowledge is
required by setting the NO_ACK bit to 0, the PTX device will enter the TX mode from the
Standby-I mode when the ARD has elapsed and the number of retry is less than the ARC.
The PTX device will enter the RX mode from the TX mode only when the EN_AA bit is set to 1
and the NO_ACK bit is cleared to 0 to receive the acknowledge packet.
RX Mode
• Primary Receive Device – PRX, PRIM_RX=1
The RX mode is an active mode where the transceiver is configured as a receiver. To enter this
RX mode from the Standby-I mode, the PRX device must set the PWR_UP bit to high, the
PRIM_RX bit to high and the CE signal to high. In this mode the receiver demodulates the
signals from the RF channel, constantly presenting the demodulated data to the packet processing
engine. The packet processing engine continuously searches for a valid packet. If a valid packet
is found by a matching address and a valid CRC, the packet payload is presented to a vacant slot
in the RX FIFO. If the RX FIFO is full, the received packet will be discarded.
The PRX device remains in the RX mode until the MCU configures it to enter the Standby-I
mode or Power Down mode. In the RX mode a carrier detection signal, CD, is made available.
The CD signal is set high when an RF signal is detected on the receiving frequency channel. The
internal CD signal is filtered before being written into the CD register. The RF signal must be
present for at least 128 μs before the CD signal is set high.
The PRX device will enter the TX mode from the RX mode only when the EN_AA bit is set to
1 and the NO_ACK bit is cleared to 0 in the received packet to transmit an acknowledge packet
with a pending payload in the TX FIFO.
RF Transceiver Packet Processing
Packet Format
The complete packet includes a preamble, 3~5 address bytes, a packet control field, 0~32 payload
bytes and a CRC field.
P�ea��le
(1 �yte)
Add�ess
(3~5 �ytes)
Pa�ket Cont�ol
Payload
CRC
(9/0 �its)
(0~3� �ytes) (�/1 �ytes)
Payload Length
(6 �its)
PID
(� �its)
Packet Format
NO_ACK
(1 �it)
Rev. 1.10
161
December 22, 2014