UPD78323 NEC, UPD78323 Datasheet - Page 30

• Manufacturer Part Number: UPD78323
• Description: 16/8-BIT SINGLE-CHIP MICROCONTROLLER
• Manufacturer: NEC

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3. BLOCK FUNCTIONS
3.1
If no bus cycle startup request is made from the EXU, a prefetch address is generated and instruction prefetch is carried
out. The prefetched instruction code is fetched into the instruction queue.
3.2
byte RAM is built in the EXU.
3.3
3.4
processed by the context switch, vectored interrupt or macro service function.
In the BCU, the necessary bus cycle is started according to the physical address obtained by the execution unit (EXU).
In the EXU, address calculation, arithmetic logical operation and data transfer are controlled by microprograms. A 256-
The 256-byte RAM in the EXU is accessible by the relevant instruction faster than peripheral RAM (768 bytes).
This block consists of a 32K-byte ROM and a 768-byte RAM. However, the PD78323 does not incorporate ROM.
ROM access can be disabled by EA pin.
Various interrupt requests (NMI, INTP0 to INTP6) generated either externally or from the peripheral hardware are
The 3-level interrupt priority is also specified.
BUS CONTROL UNIT (BCU)
EXECUTION UNIT (EXU)
ROM/RAM
INTERRUPT CONTROLLER
PD78323, 78324