Hi Geoff,

RM> GW> Could someone tell me what i should divide my connect speed by to get
RM> GW> cps?

  | 1 Start bit | 5 - 8 Data bits | 0 - 1 Parity bit | 1 - 2 Stop bits |

______ s dddddddd p s ___________
      |_|XXXXXXXX|X|_|
  
a uart frames a byte of data and adds parity if required

you might have seen in dos
mode com1:9600,n,8,1
9600 = baud
n = no parity
8 data bits
1 = 1 stop bit
or
mode com1:2400,e,7,1
2400 = baud
e = even parity
7 = 7 data bits
1 = 1 stop bit

baud is transmitted bits per second
a transmitted byte always begins with 1 start bit
followed by usually 7 or 8 data bits
followed by 0 or 1 parity bit
followed by usually 1 stop bit

start data p   stop
1  +  8  + 0 + 1  =  10 baud for 8 bit characters
or
1  +  7  + 1 + 1  =  10 baud for 7 bit characters

for these examples, divide the baud rate by 10

9600 baud = 960 characters / second or 7680 bits / second
2400 baud = 240 characters / second or 1920 bits / second

28800 baud = 2880 characters / second or 23040 bits / second
usually 8 bit character, no parity, 1 stop bit


now to confuse the issue
a uart can send a 5,6,7 or 8 bit character and 1 or 2 stop bits
from 7 bits for 5,n,1 mode,   divide by 7  = characters
to 12 bits for 8,e,2 mode,    divide by 12 = characters

Colin.
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