Electronic Components Datasheet Search |
|
RFM75 Datasheet(PDF) 9 Page - List of Unclassifed Manufacturers |
|
RFM75 Datasheet(HTML) 9 Page - List of Unclassifed Manufacturers |
9 / 27 page Page 9 of 27 RFM75 V1.0 E‐mail:sales@hoperf.com website://www.hoperf.com 5.1.1 Preamble The preamble is a bit sequence used to detect 0 and 1 levels in the receiver. The preamble is one byte long and is either 01010101 or 10101010. If the first bit in the address is 1 the preamble is automatically set to 10101010 and if the first bit is 0 the preamble is automatically set to 01010101. This is done to ensure there are enough transitions in the preamble to stabilize the receiver. 5.1.2 Address This is the address for the receiver. An address ensures that the packet is detected by the target receiver. The address field can be configured to be 3, 4, or 5 bytes long by the AW register. The PRX device can open up to six data pipes to support up to six PTX devices with unique addresses. All six PTX device addresses are searched simultaneously. In PRX side, the data pipes are enabled with the bits in the EN_RXADDR register. By default only data pipe 0 and 1 are enabled. Each data pipe address is configured in the RX_ADDR_PX registers. Each pipe can have up to 5 bytes configurable address. Data pipe 0 has a unique 5 byte address. Data pipes 1-5 share the 4 most significant address bytes. The LSB byte must be unique for all 6 pipes. To ensure that the ACK packet from the PRX is transmitted to the correct PTX, the PRX takes the data pipe address where it received the packet and uses it as the TX address when transmitting the ACK packet. On the PRX, the RX_ADDR_Pn, defined as the pipe address, must be unique. On the PTX the TX_ADDR must be the same as the RX_ADDR_P0 on the PTX, and as the pipe address for the designated pipe on the PRX. No other data pipe can receive data until a complete packet is received by a data pipe that has detected its address. When multiple PTX devices are transmitting to a PRX, the ARD can be used to skew the auto retransmission so that they only block each other once. 5.1.3 Packet Control When Dynamic Payload Length function is enabled, the packet control field contains a 6 bit payload length field, a 2 bit PID (Packet Identity) field and, a 1 bit NO_ACK flag. Payload length The payload length field is only used if the Dynamic Payload Length function is enabled. PID The 2 bit PID field is used to detect whether the received packet is new or retransmitted. PID prevents the PRX device from presenting the same payload more than once to the MCU. The PID field is incremented at the TX side for each new packet received through the SPI. The PID and CRC fields are used by the PRX device to determine whether a packet is old or new. When several data packets are lost on the link, the PID fields may become equal to the last received PID. If a packet has the same PID as the previous packet, RFM75 compares the CRC sums from both packets. If the CRC sums are also equal, the last received packet is considered a copy of the previously received packet and discarded. NO_ACK The NO_ACK flag is only used when the auto acknowledgement feature is used. Setting the flag high, tells the receiver that the packet is not to be auto acknowledged. The PTX can set the NO_ACK flag bit in the Packet Control Field with the command: W_TX_PAYLOAD_NOACK. However, the function must first be enabled in the FEATURE register by setting the |
Similar Part No. - RFM75 |
|
Similar Description - RFM75 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |