System Booting Flowchart - Yamaha P-105B Service Manual

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SYSTEM BOOTING FLOWCHART

Power On
Set
CPU, each registers
Initialize BOOT SDRAM
0 clear, Setup of
constant
Initialize SWX port
Scanning SW
(PB0-PB3)
PA0 = L → H → L
(IC1, A20)
PA1 = L → H → L
(IC1, B19)
PA2 = L → H → L
(IC1, A19)
PA3 = L → H → L
(IC1, D18)
NO
Installation
mode ?
YES
Starts installation mode
(REC LED blinks)
END
*1 As for the safe check, it checks whether the mute functions correctly when the pulse from ERR-DETECT is interrupted.
*2 "Factory Set" refers to the condition of turning on the power after executing "Factory Set" in the Test Program.
Starts accessing to IC18
If not, IC1 may be
defective
Starts accessing to IC8
If not, IC18 may be
defective
P-105B/P-105WH/P-35B/L-85WH/LP-5AWH
P-105B/P-105WH
Port initial setting
SPOFF = H (IC1, T2)
MUTE = H (IC1, T3)
ERR-DETECT =
L (IC1,PH6)
Pulse is output from
ERR-DETECT
(IC1, PH6)
Start scanning to
SW, LED and key
NO
Test Mode ?
YES
Starts Test Mode
(A3 sine wave is output)
END
MUTE = L (IC1, T3)
SPOFF = L (IC1, T2)
If the "Safe check" result is NG,
booting will stop. In that case,
check abnormality detection
circuit by Test Mode.
NG
Safe check ?
(*1)
OK
END
After
YES
executing
Factory Set ?
(*2)
PLAY and REC LEDs blink until
NO
Factory Set completion
Depending on whether
headphones are
inserted or not.
Main routine
57