UMAX140610. LIN
– J1939 CAN Protocol Converter with PWM Output. Version 1
Page: 63-81
For more information on the LIN interface,
see: “Interior Ambient Lighting Module with LIN
Interface User
’s Guide. Microchip Technology Inc., 2008.”
4.4.1.2 CAN bus
A dedicated J1939 proprietary message with the following parameters will be used to control
the light intensity of the red, green and blue components of the module LED:
Transmission Repetition Rate:
0.5 sec
Data Length:
8
Default Priority:
6
Parameter Group Number:
65280 (Proprietary B)
Start Position
Length
Parameter Name
SPN
1
1 byte
IntensityRed
N/A
2
1 byte
IntensityGreen
N/A
3
1 byte
IntensityBlue
N/A
Parameter Name:
IntensityRed, IntensityGreen, IntensityBlue
Data Length:
1 byte
Resolution:
0.4 %/bit
Offset:
0
Type:
Measured
4.4.2 Configuration Steps
As a first step, create a block diagram of the required converter configuration using the
converter function blocks, Figure 32. Then, configure each individual function block, see Figure
32.
Start from LIN signals. Configure constant LIN signal containing: SelectIntensity, RampUp, and
DimDown as
LIN Signal #1
. Set
Signal Type
to
Scalar
,
Size
to
8 bit
,
Encoding Type
to
BCD
Value
and
Init Value Scalar
to
0x1F
, see Figure 33.
Then configure
LIN Signal #2
as RedSaturation signal, see: Figure 34. This signal will have
CAN Receive #1
as
Input Signal Source
and
Physical Value
as
Encoding Type
.
Min Value
,
Max Value
,
Scale
and
Offset
will be set to convert 0…100% physical value to 0x00…0xFF LIN
signal range:
MinValue
= 0;
MaxValue
= 0xFF;
Offset
= 0 [%];
Scale
= 100%/0xFF=0.3922 [%/Bit]
Configure
LIN Signal #3
and
LIN Signal #4
in a similar way as GreenSaturation and
BlueSaturation signals, connecting them to:
CAN Receive #2
and
CAN Receive #3
,
respectively, see Figure 35 and Figure 36.
