
CHAPTER 1 INTRODUCTION
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1.6.2 Internal units
(1) CPU
Executes almost all instruction processing such as address calculation, arithmetic/logic operation, and data
transfer in 1 clock by using a 5-stage pipeline.
Dedicated hardware devices such as a multiplier (16 bits x 16 bits
32 bits) and a barrel shifter (32 bits) are
provided to increase the speed of processing complicated instructions.
(2) Bus control unit (BCU)
Initiates the necessary number of external bus cycles based on the physical address obtained by the CPU.
If the CPU does not issue a request to start a bus cycle when an instruction is fetched from the external memory
area, generates a prefetch address to prefetch an instruction code. The prefetched instruction code is loaded
to the internal instruction queue.
(3) ROM
Internal ROM mapped starting from address 00000000H. Enable/disable of access can be specified by the
MODE pin in the μPD703003 and 70F3003.
On the other hand, the ROM is fixed to the access enable irrespective of the MODE pin status in the
μPD703003A, 70F3003A and 703005A.
This Internal ROM is accessed in 1 clock by the CPU when an instruction is fetched.
(4) RAM
Internal RAM mapped starting from address FFFFE000H. This Internal RAM can be accessed in 1 clock by
the CPU when data is accessed.
(5) Interrupt controller (INTC)
Processes interrupt requests (NMI, INTP110 to INTP113, INTP120 to INTP123, INTP130 to INTP133, and
INTP140 to INTP143) from the internal peripheral hardware and external sources. Eight levels of priorities
can be specified for these interrupt requests, and multiplexed processing control can be performed on an
interrupt source.
(6) Clock generator (CG)
By the internal PLL, supplies the CPU clock whose frequency is five times, one time, or 1/2 times the frequency
of the oscillator connected across the X1 and X2 pins. Input from an external clock source can also be
referenced instead of using the oscillator.
(7) Real-time pulse unit (RPU)
Provides four 16-bit timer/event counter channels, one 16-bit interval timer channel, and capabilities for
measuring pulse width and generation of programmable pulse outputs.
(8) Serial interface (SIO)
The serial interface consists of 4 channels in total of asynchronous serial interfaces (UART) and synchronous
or clocked serial interfaces (CSI). Two of these channels can be switched between UART and CSI, and the
other two channels are fixed to CSI.
UART transfers data by using the TXD and RXD pins and the CSI transfers data by using the SO, SI, and
SCK pins.
The output of the baud rate generator and system clock can be selected as the serial interface clock source.
Of the fixed CSI, one channel is the serial clock output and serial output is the open drain output.