AeroComm ZB2430 I N T E R F A C E T I M E O U T / R F P A C K E T S I Z E, F L O W C O N T R O L

2 2

S E R I A L I N T E R F A C E

	20
Stop Bit Delay =	(----------------------------------------------Baud Rate × 1ms)

E N G I N E E R ’ S T I P

Using a non-standard baud rate.

The ZB2430 supports a majority of standard as well as non-standard baud rates. To select a standard baud rate, use the value shown for EEPROM address 0x42 in Table 5 above. To enable a non-standard baud rate, program EEPROM address 0x42 (Custom Baud Enable) to 0xE3 and then use the equation above to solve for BAUD_M and BAUD_E.

I N T E R F A C E T I M E O U T / R F P A C K E T S I Z E

Interface Timeout – Interface Timeout specifies a maximum byte gap between consecutive bytes. When that byte gap is exceeded, the bytes in the transmit buffer are processed as a complete packet. Interface Timeout (EEPROM address 0x58), in conjunction with the RF Packet Size, determines when a buffer of data will be sent out over the RF as a complete RF packet, based on whichever condition occurs first.

RF Packet Size - RF Packet Size is used in conjunction with Interface Timeout to determine when to delineate incoming data as an entire packet based on whichever condition is met first. When the transceiver receives the number of bytes specified by RF Packet Size (EEPROM address 0x5A) without experiencing a byte gap equal to Interface Timeout, that block of data is processed as a complete packet. Every packet the transceiver sends over the RF contains extra header bytes not counted in the RF Packet Size. Therefore, it is much more efficient to send a few large packets than to send many short packets.

Stop Bit Delay - For systems using the RS-485 interface, the RS-485 DE pin might be deasserted Low too quickly at the end of a packet (especially at slower interface baud rates). Stop Bit Delay (EEPROM address 0x3F) controls how long RS-485 DE should be left High at the end of a packet before dropping it Low and disabling the RS-485 driver circuitry. Generally, it should be set greater than or equal to two byte times.

F L O W C O N T R O L

Although flow control is not required for transceiver operation, it is recommended to achieve optimum system performance and to avoid overrunning the ZB2430’s serial buffers. The ZB2430 uses seperate buffers for incoming and outgoing data.