ELM327
Programmable Parameter Summary (continued)
PP
Description
Values
Default
Type
29
Printing of the CAN data length (DLC) when printing header bytes
(AT D0/D1 default setting)
00 = ON
FF = OFF
FF
D
(OFF)
2A
CAN Error Checking (applies to protocols 6 to C)
Each bit of this byte controls an option, as follows:
00 to FF
38
D
(00111000)
b7: ISO15765 Data Length
b6: ISO15765 PCI = 00
b5: Search after ERR94
b4: Search after LV RESET
b3: Wiring Test
0: accept any 1: must be 8 bytes
0: allowed
0: normal
0: normal
0: bypass
1: not allowed
1: CAN is blocked
1: CAN is blocked
1: perform
b2 to b0: reserved for future - leave set to 0
2B
2C
Protocol A (SAE J1939) CAN baud rate divisor.
01 to 40
00 to FF
02
R
R
(250 Kbps)
The protocol A CAN baud rate is determined by this value
rate (in kbps) = 500 ÷ value
For example, setting this PP to 19 (ie. decimal 25) provides
a baud rate of 500/25 = 20 kbps.
Protocol B (USER1) CAN options.
E0
(11100000)
Each bit of this byte controls an option, as follows:
b7: Transmit ID Length
b6: Data Length
0: 29 bit ID
1: 11 bit ID
0: fixed 8 byte 1: variable DLC
b5: Receive ID Length
b4: baud rate multiplier
0: as set by b7 1: both 11 and 29 bit
0: x1
1: x 8/7 (see note 3)
b3: reserved for future - leave set at 0.
b2, b1, and b0 determine the data formatting options:
b2 b1 b0
Data Format
none
ISO 15765-4
SAE J1939
0
0
0
0
0
1
0
1
0
Other combinations are reserved for future updates – results will
be unpredictable if you should select one of them.
2D
2E
2F
Protocol B (USER1) baud rate divisor. See PP 2B for a description.
Protocol C (USER2) CAN options. See PP 2C for a description.
Protocol C (USER2) baud rate divisor. See PP 2B for a description.
01 to 40
00 to FF
01 to 40
04
R
R
R
(125 Kbps)
80
(10000000)
0A
(50 Kbps)
Notes: 1. The ELM327 does not accept decimal digits for the Programmable Parameters - all values are hexadecimal.
2. For Programmable Parameters that describe options in terms of bits, b7 is the msb, and b0 is the lsb.
3. When b4 of PP 2C or PP 2E are set, the CAN baud rate will be increased by a factor of 8/7, but the baud
rate displayed by the AT DP command will still show the base rate (as set by PP 2D or PP 2F). For example,
if you set PP 2C b4 to 1, and then PP 2D to 06, the base frequency will be 83.3 kbps. The AT DP command
will report 83 kbps, but the actual baud rate will be 83.3x8/7 = 95.2 kbps.
ELM327DSI
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