PC Peripheral IC
   
 
Q1 :  The curve is good on black (dark) surface, but NG when white surface.
Q2 :  The curve is good on white surface, but NG when black (dark) surface.
Q3 :  The curve is NG on all surfaces.
Q4 :  The curve jitters when lifting the mouse between 5 ~ 15mm from surface.
Q5 :  What is USB ? How can I design a USB Mouse using Elan Ics?
Q6 :  I have sent the data to USB FIFO, but the UDC doesn’t send the data to the host PC. Is there anything I should know?
Q7 :  How do I use the remote key to weak up MCU while host (PC) suspends and EM78M680 MCU is in the power down mode?
Q8 :  What the reference voltage is in the ADC function of EM78M680? Anything I should know when using V33 pin as the current source?


  Answer
Q1 :   The curve is good on black (dark) surface, but NG when white surface.
  A:Maybe particles fall on the sensor cells! Replace the sensor with a new one.


Q2 :   The curve is good on white surface, but NG when black (dark) surface.
  A:Maybe not enough lightness! Change the resistance *R1 as the min. value(33Ω) or resistance *R2 as the min. value (OM02: 8.2KΩ, OM10:2KΩ) or if R1 or R2 is already the min.value,you should choose the better(lighter) LED。 PS: Refer to "OM02-Spec050419" P.6~P.7 or ‘OM10A (V1.1)070503’ P.13 to *R1 and *R2 value.


Q3 :   The curve is NG on all surfaces.
  A:Maybe focus or light source is NG! Check the structure designed or position of spot light,and then replace better lens if necessary. PS: Refer to"OM01&02-AN050419" P.10 to structure designed and position of spot light check.


Q4 :   The curve jitters when lifting the mouse between 5 ~ 15mm from surface.
  A:Maybe noise disturbance! Choose the recommended application circuit and structure. PS: Refer to"OM01&02-AN050419" P.11 to recommended application circuit and structure.


Q5 :   What is USB ? How can I design a USB Mouse using Elan Ics?
  A:Universal Serial Bus (USB) is an interface between computer and its peripherals.The detail of USB and the specification you can find in the official webside of USB: www.usb.org Elan have many support tools that special designed for the developer who are working on USB devices. Such as ICE (In Circuit Emulator) with USB interface, Inspector of USB bus, Guide books…ext. Undoubtedly, we also have experienced engineers to help our customers solve any kind of problem which are faced.


Q6 :   I have sent the data to USB FIFO, but the UDC doesn’t send the data to the host PC. Is there anything I should know?
  A:The USB architecture follows "Master/Slave" rule. USB device is a slave and PC host is a master. There will be no data transmission between the host (PC) and device unless the host sends the request to get data. (So, even you sent data to FIFO, the UDC still couldn't send the data if the host didn't send the request.) Please check the correctness of your device description; configuration description; … e.t.c. Only when all descriptions are correct, host may continue to send the request (In toke) to the device.


Q7 :   How do I use the remote key to weak up MCU while host (PC) suspends and EM78M680 MCU is in the power down mode?
  A:When host suspends, EM78M680 can enter the sleep mode. The control bit of sleep mode is in the IOCE bit 4. There are two ways to weak up EM78M680 from sleep mode: 1. PORT CHANGE WEAKUP – MCU can weak-up by specific I/O ports change. (You should set the IOCE bit 6 before entering sleep mode). The remote weak-up function enable/disable depends on the setting in the PC device manager. 2. HOST RESUME- Host resume also can weak up the MCU. For weak-up function setting, process please refer the suspend interrupt subroutine of the interrupt demo code.


Q8 :   What the reference voltage is in the ADC function of EM78M680? Anything I should know when using V33 pin as the current source?
  A:1.The ADC reference voltage is 3.3V. We don't suggest you use the V33 as current source in the application circuit while you use the ADC function. This will influence ADC result correctness. 2.The internal regulator can offer no more than 60mA. Don't draw more than 60mA from V33 pin. Otherwise the regulator output voltage will decrease and result in V33 voltage unstable; in this case any unexpected condition will happen. (For example: PC can't detect the USB device….). Please make sure the current from V33 is under maximum limit when using V33 as the current source.