Huawei MU509 - LED Interface Compatibility Design; Detailed Interface Differences; LED Interface Design Guide

HUAWEI 30 mm × 30 mm LGA Module
Hardware Migration Guide
LGA Interface Differences
Issue 08 (2016-12-12)
HUAWEI Proprietary and Confidential
Copyright © HUAWEI Technologies Co., Ltd.
46
"**" means do not install at first, but C1, C2 and C3 need to reserve the capacitor pads in order
to deal with filter common and differential mode interference.
2.11 LED Interface Compatibility Design
2.11.1 Detailed Interface Differences
Table 2-18 Differences of LED control signal
Pin
No.
Interface
Name
MU509
MC509
MU609
ME209u
-526
ME909u
MU709
ME909s
91
LED
LED_STATUS
Y
Y
Reserved
101
LED_MODE
Y
Y
Y
Y
Y
Y
Y
2.11.2 LED Interface Design Guide
Pin 91 and pin 101 are worked as LED control signals, which are the current sink
type; and the drive strength is 10 mA.
For the pins of current sink type, it is recommended that you connect the pins based
on the circuit diagram shown in the following figure. R1 and R2 can be adjusted
according to the actual LED brightness. The VCC voltage must not exceed VBAT
+0.5 V; otherwise, the internal chip of a module may be damaged. It is recommended
that you use the VBAT as the VCC.
For the details about the LED working status, you can refer the product's hardware
guide.
Figure 2-26 Circuit of the LED interface