Moxa DA-683-SP-LX [10/47] Warning

DA-683 Hardware Introduction

1-7

If you are a programmer and you need to write a driver for your serial device, then you may need to use

formula A. If you have a serial device that requires using a non-standard baudrate, then you can use formula

B to determine if the DA-683 supports a baudrate within the tolerance specified by the serial device

manufacturer.

Example: Your serial device requires using a baudrate of 5340 bps and has a tolerance of 2 bps. Can the

DA-683 be used with this device?

Solution: Set formula B to the desired baudrate and then solve for K.

8 x 912600/K = 5338 ==> K = 1367.703259…

This shows that the supported baudrate closest to 5340 comes from setting K=1367 or K=1368.

K=1368 ==> Baudrate1 = 5336.842105...

K=1367 ==> Baudrate2 = 5340.746159…

Since 5338 – Baudrate1 < 2, we can see that the DA-683 supports the serial device.

Note that we can use formula A to generate the so-called “standard” baudrates, which come from setting M=0,

and setting N equal to certain integers.

Standard Baudrates

Baudrate N M Baudrate N M

115200 8 0 1800 512 0

57600 16 0 1200 768 0

38400 24 0 600 1536 0

19200 48 0 300 3072 0

9600 96 0 150 6144 0

7200 128 0 75 12288 0

4800 192 0 50 18432 0

2400 384 0

WARNING

Communication between a serial device and a Moxa UART port may not work correctly if the serial device uses

a baudrate that it not within the correct tolerance of a baudrate calculated from either formula A or formula B.