25
PSR-E223/YPT-220
SYSTEM BOOTING FLOWCHART
Power On
Set CPU Register
Initialize Work RAM
YES
NO
Turns ON the SoftPower
(IC101 117pin PF0)
Starts accessing to internal
RAM
Initialize LCD
SoftPower = H
Initialize Port
&
LCD EN = L
LCD RS = L
If the power is turned off when
you release the power switch after
this stage, the SoftPower circuit
board (PNAM TR102 peripheral)
is defective
If the booting procedure does
not reach this stage, the CPU or
device around the CPU is defective
Starts accessing to LCD
Driver (IC301)
Opening indication
( “YAMAHA” )
In case of no indication,
the LCD or LCD Driver
(IC301) is defective
Starts keyboard scanning
Starts outputting signals from
B01–B11
* Turn on the power while holding down the
[C#2], [F2] and [G#2]
Test Program ?
Test Program
( “TEST” ) indication
The keyboard is defective if it is
impossible to enter the test
Sound can be played on the
keyboard
Main screen
( “GrandPno” )
indication
Normal operation
Test program routine
