NEC NP-NC900C-A Service Manual page 13

The Main Flow Chart of Slave MCU
(main loop)
System Monitoring Processes
N
(Monitor all of the Fans status,
(Normal
Thermal management, CW-Cover
Standby
detection, Bi-Metal detection etc)
Mode)
UART Command Processes
- Parse command from receive buffer.
- Execute command.
Notes:
- The Slave MCU will always running the main loop after the Master assert the MPWR+ signal, the Slave MCU
should not stuck in any error state.
- If Slave MCU detected any system error,
- The Slave MCU asserts the ALERT signal.
- The Master should send query command to Slave to get error code back.
- The Slave MCU waiting Master's instruction to execute following operation.
"Confidential, Do Not Duplicate without written authorization from NEC."
TROUBLESHOOTING
Slave MCU
Start
Slave MCU Boot Up
Initialize processes
Does projector in
power on state?
Y
(Power ON Mode)
(Detected system error)
The Slave MCU will start here by below condition:
1. When Master assert the MPWR + signal.
2. When MPWR + has asserted and Master assert
RESET signal, the Slave MCU will restart.
- The Slave MCU perform the necessary initial setting and
control, ex: GPIO initial control, set timer, UART etc.
The Power ON state means the Slave MCU has got the
"Power ON" command from Mater and has executed the
Power ON processes, otherwise the Slave MCU is stay in
"Normal Standby".
- The Slave MCU assert ALERT signal
to Master.
- The Slave MCU should ready current
error information for Master to query.
- Parse command
The Slave MCU will send ACK back to Master if received
command is legul, or send NAK if received command is ilegal.
4-3