Sam4s SPS-500, Service Manual

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SAM4S SPS-500 SERIES 6-1
6 Troubleshooting
6-1 System power-up sequence
The following lists the chain of events that occur when you turn on the POS. You can follow this list as one
means of determining if the POS is operating correctly.
When the power switch is turned on, these events occur:
6-1-1 Main B’D power-up sequence
 All devices (CPU, Memory, Controller…etc,) are reset.
 The power ( 3.3V) LED are light on MAIN B’D.
 The boot program (A29L800UV) is run and the status LED is on.
 The OS & application program is copy from NAND-Flash to SDRAM (64Mb).
It takes about 30 sec and the status LED is off.
 Now, Application program is run on SDRAM and TFT-LCD is displayed.
6-1-2 IO B’D power-up sequence
 All devices (micom, Memory…etc,) are reset.
 The power ( 5V,3.3V) LEDs are light on IO B’D.
 And than, IO B’D is waiting for communication with main B’D.
6-1-3 LCD B’D power-up sequence
 The micom (ATMEGA8) is reset.
 The power(5V) LED are light on LCD B’D
 The Rear 2Line LCD are displayed
 And than, LED B’D is waiting for communication with main B’D.