Matrix Orbital GLT240128 Legacy - Manual (Page 26)

4.6 Setting a Non-Standard Baud Rate
Syntax Hexadecimal 0xFE 0xA4 [speed]
Decimal 254 164 [speed]
Parameters Parameter Length Description
speed 2 Inputed LSB MSB from baud rate
formula (12-2047).
Description This command sets the RS-232 port to a non-standard baud rate. The
command accepts a two byte parameter that goes directly into the
modules baud generator. Use the formula, speed
=
CrystalSpeed
8×DesiredBaud
− 1 to
calculate the [speed] for any baud rate setting. The speed can be
anywhere from 12 to 2047 which corresponds to a baud range of 977 to
153,800 baud. Setting the baud rate out of this range could cause the
display to stop working properly and require the Manual Override
jumper to be set.
Remembered Always
Examples
Crystal Speed 16 Mhz
Desired BAUD 13,500
speed =
crystalspeed
8 ∗ DesiredBaud
−1
speed = 148
.
15 − 1
speed =
16
,
000
,
000
8 ∗ 13
,
500
− 1
speed = 147
.
15
• LSB = 0x93 (rounded)
• MSB = 0x00
• Intended Baud Rate: 13,500 baud
Actual Baud Rate:
16
,
000
,
000
8 (147+1)
=13,514 Percent Difference: 0.1%
NOTES
• Results from the formula are rounded down to the nearest whole number (i.e 73.07
= 73).
• This formula becomes less acurate as baud rates increase, due to rounding.
• Place the speed result backwards into the formula to receive the actual baud rate.
(Baud =
CrystalSpeed
8 (speed+1)
)
• The actual baud rate must be within 3% of the intended baud rate for the device to
communicate.
Matrix Orbital GLT240128 21