Using EVM without MCU (MSP430), Standalone Mode
57
SNVU382A – April 2014 – Revised June 2014
Copyright © 2014, Texas Instruments Incorporated
Quick Start Guide
D.9
Using EVM without MCU (MSP430), Standalone Mode
NOTE:
The assumption is that LP8860-Q1 EEPROM has the default content. If modifications have
been done, follow the steps described in
to restore original EEPROM settings
before proceeding.
By default (original EEPROM setting of the LP8860-Q1 on the EVM), LED brightness is controlled through
I
2
C/SPI registers.
For operation without MCU, the most straightforward way to control brightness is to use an external PWM
input signal.
To use PWM input pin for brightness control, the EEPROM setting needs to be modified using the
following procedure:
1. Make sure LED brightness is 0%. Also check that PLL is disabled in
LED drivers
tab.
2. Unlock EEPROM.
3. In
LED drivers
tab for
Display brightness mode
select
PWM input pin duty cycle control
.
4. To save new setting in EEPROM – Burn EEPROM.
Check that EVM is powered as follows:
•
Connect 5-V power supply to J6. Check jumper J8, it should be at “EXT” (EXT RAIL) position.
•
Connect V
BATT
(12 V) to J2.
To disconnect MCU from the LP8860-Q1 remove all jumpers from J11. External control can then be
connected to the left side of the connector J11 (see