66 of 83ELM329DSC Elm Electronics – Circuits for the Hobbyist
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Programmable Parameter Summary (continued)
PRS232 baud rate divisor when pin 6 is high (logic 1)
The baud rate (in kbps) is given by 4000 ÷ (PP 0C value)
For example, 500 kbps requires a setting of 8 (as 4000/8 = 500)
Here are some example baud rates, and the hex divisor to be used
(the decimal values are for your convenience, but can not be used):
68
(38.4)
01 to FF0C
Note: The ELM329 can only process continuous byte receives at
rates of 700 kbps or less. If you need to connect at a higher
rate, consider adding a delay between the bytes to maintain
an average rate of 70k bytes per second, or less.
PP Description Values Default Type
0D Carriage Return Character
used to detect and send line ends
R0D00 to FF
0E 9A
(10011010)
00 to FFPower Control options
Each bit of this byte controls an option, as follows:
b7: Master enable 0: off 1: on
if 0, pins 15 and 16 perform as RTS and Busy
(must be 1 to allow any low power functions)
b6: Pin 16 full power level 0: low 1: high
normal output level, is inverted when in low power mode
b5: Auto LP (RS232) control 0: disabled 1: enabled
allows low power mode if the RS232 activity stops
b4: Auto LP (RS232) timeout 0: 5 mins 1: 20 mins
no RS232 activity timeout setting
b3: Auto LP (RS232) warning 0: disabled 1: enabled
if enabled, says ‘ACT ALERT’ 1 minute before timeout
b2: Pin 15 function 0: RTS 1: IgnMon
for use as IgnMon input, b7 must also be ‘1’
b1: Ignition delay 0: 1 sec 1: 5 sec
delay after IgnMon (pin 15) returns to a high level, before
normal operation resumes
b0: reserved for future - leave set at 0
R
Baud Rate
(kbps)
19.2
38.4
57.6
115.2
230.4
PP 0C value
D0
500
208
68
45
23
11
08
104
69
35
17
8
hex dec
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