ELM327P datasheet(41/51 Pages) ELM

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ELM327

Programmable Parameters (Cont’d)

Notes:

1. The “Type” column indicates when changes to the Programmable Parameter take effect. Possible values

are:

I - the effect is immediate,

D - takes effect after Defaults are restored (AT D, AT Z, AT WS or power off/on)

R - will only become apparent after a Reset (AT Z, AT WS or power off/on)

P - only takes effect after power off/on or AT Z.

2. These are changes since the last version of the IC.

Printing of the CAN data length (DLC) when printing header bytes

(see note 2)

(OFF)

Description

Values

Default

Type

Protocol B (USER1) CAN protocol options.

(10000000)

(50 Kbps)

Protocol B (USER1) baud rate divisor. See PP 2B for a description.

00 to FF

(11100000)

(125 Kbps)

01 to 40

00 to FF

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

Each bit of this byte controls an option, as follows:

b7: Transmit ID Length, 0=29 bit ID, 1=11 bit ID

b6: Data Length, 0=fixed 8 byte, 1= Variable DLC

b5: Receive ID Length, 0=as set by b7, 1=both 11 bit and 29 bit

b4: reserved for future - leave set at 0

b3: reserved for future - leave set at 0.

b2, b1, and b0 determine the data formatting options, as follows:

Data Format

none

ISO 15765-4

SAE J1939

Other combinations are reserved for future – results might be

unpredictable if you should select one of them.

Note that b7 is the msb, and b0 is the lsb. For example, the default

value of E0 can be shown as 11100000 in binary, which has b7, b6

and b5 set to 1’s. This means that by default, 11 bit IDs will be

sent, the data length will vary, and the ELM327 will receive

messages with either 11 or 29 bit IDs.

Protocol A (SAE J1939) CAN baud rate divisor.

(250 Kbps)

01 to 40

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.

00 = ON

FF = OFF

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