Sony PCS-1500 Service Manual page 108

3-2. Circuit Description of the Respective Boards
[SIRCS block]
Internal Circuit of IC110
SIRCS Interrupt
Read "0400000Ah"
\HCS_TDM
HA1-4
4
from/to
\HRD
CPU BLOCK
\HWR
HD0-7
8
\RES_ALL
The SIRCS block consists of the selector circuit (IC781, IC782) that selects the received SIRCS signal
from either the camera (PCS-C150/C150P) or the RX-47 board, and the microcontroller that decodes the
selected received SIRCS signal and encodes (with modulating by the carrier wave) the SIRCS signal to be
transmitted from IR-OUT (refer to Fig. 3-10). Because the microprocessor (IC780) has only a general-
purpose port, it cannot be connected directly to the CPU bus. The microcontroller (IC780) is connected
to the CPU bus indirectly by connecting it to the I/O port of TDM-ASIC (IC750 of NETIF block). The
interrupt signal is latched inside IC110 (CPU block) so that the level triggered interrupt are realized.
The operating clock (4 MHz) of the microcontroller (IC780) is generated by the crystal oscillator (X780).
The SIRCS block is reset by the "RES_ALL" signal that is supplied from the CPU block.
It operates on the +5 V power supply voltage.
3-18
\IRQ_SIR
Q
Clear
TDM ASIC(IC750)
uPD65646GJ-171
\STROBE,DECDAT
\HCS Port-A
7-0
8
HA
3-0
REQUEST
\HRD Port-D
\HWE
ENCDAT
HD Port-C
7-0 7-0
8
STATUS
Port-B
DECSET
Port-F
\RESET Port-E
7
Fig. 3-10 SIRCS Block & Connecting with Bus
SIRCS Encoder/Decoder(IC780)
uPD17216GT-560
P0E
2
Selector Circuit(IC781,782)
SIRCS IN
P0D
3-0
INT
P0C
3-0
P0E
0
P0B
3-0
P0A
3-0
REM
P0E
1
P0E
3
\WDOUT
\RESET
from Camera
0
from RX-47 board
1
to IR OUT
PCS-1500/1500P