Daewoo DSD-9251MAV, Service Manual

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13
CIRCUIT OPERATION MANUAL
NOTPGM_EN (PIO1_3)
Flash ROM Write protect/ Program enable (Low) or Program disable (High)
SLOW_S/W (PIO1_4)
Checking the connection of external features with Vcr scart such as VCR and general power on/off status. Connect and
power on(High), Not connect or power off(Low)
RS232_Tx (PIO1_5)
RS232_Rx (PIO1_6)
Rs232 serial data transfer (Used to S/W upgrade, Debugging)
KI1 (PIO2_7)
Key input check. Reading Keys when in the Low status.
COM0 (PIO3_0)
COM1 (PIO3_1)
COM2 (PIO3_2)
COM3 (PIO3_3)
COM4 (PIO3_4)
Selecting 4 Digit of the Display, including clock dots. If it s in Los status, the Digit will be in ON status.
SegA/K0 (PIO4_0)
SegB/K1 (PIO4_1)
SegC/K2 (PIO4_2)
SegD/K3 (PIO4_3)
SegE/K4 (PIO4_4)
SegF/K5 (PIO4_5)
SegG/K6 (PIO4_7)
Seg_clk/K7 (PIO3_5)
Signals the segment of Display and Dot (is ON when in High status) and Key Scan.
Trigger IN (PIO3_6)
Trigger OUT (PIO3_7)
Used when debugging with DCU Tool
REMOCON_IN (PIO4_6)
Recognize the REMOCON signal being sent from IR Sensor.
(5) Memory Interface
Sti5518 can support both On-chip memories that are 2KB SRAM, 2KB SRAM or Data Cache and 2KB Instruction
Cache and external expanded memories as of ROM and DRAM. Moreover, SDRAM can be used up to 64Mbits with
MPEG memory. From the 64Mbits SDRAM 32Mbits can be used as the buffer of MPEG and the rest of 32Mbits can be
used as Code buffer enabled by Code on SDRAM program.
A. REGION 0
On-Chip memory, Handler, Trap and DMA are allotted from the address 0X80000000 to 0XBFFFFFFF.
B. REGION 1
From the address 0XC0000000 to 0XC0360000 are used as a buffer memory of MPEG.
C. REGION 2
From the address 0X00000000 to 0X3FFFFFFF, they re used for the surrounding area for the internal parts. Individual
part has 4Kbyte.
D. REGION 3
EMI (Extended Memory) is divided to 4 Banks. Bank 0 is only applicable for the DRAM Interface.