
Chapter 2
2.1.3 Hardware Summary
The following table explains the functions of the hardware in the above block
diagram. The acronyms, e.g., ACC, ALU, etc, under “Symbol” column are the
designated names of the internal function blocks. The “Address” column shows
the control registers address mapping for the corresponding control register
symbol in the “Symbol” column.
Symbol
Function
Address
ACC 8-bit
accumulator
-
ALU
8-bit 2’s-complement arithmetic logic unit
-
Multiplier
8
×
8 hardware multiplier
-
MULT
8-bit multiplicand for the multiplier
0x10
PRODH &
PRODL
PRODH hold the high byte of product result, PRODL hold
the low byte of product result
0x11
0x12
R3 Status
register
contains
status flag and page bits
0x03
R4
RAM selects register for indirect address and RAM bank
0x04
R9
Bank select register for special function control registers
0x09
Program Counter Program counter with 13 bits for 8K program ROM address
0x02
Stack
8-level hardware stacks for subroutine call and interrupt
IR
Instruction register used for instruction fetch
IR Decode
Instruction decoder to generate control signals
Address
Generator
Address generator for data RAM and control registers
-
System Control
Registers
System control registers are useful for controlling
processor, melody, I/O functions. They are memory or I/O
mapped
Tone Generator
4-channel tone generator for melody instrument synthesis
-
Prescaler
Pre-scales the timing clock before entering the counter
TCC
General-purpose timer with interrupt function
0x01
MTC
General-purpose/melody timer with interrupt function
0x06
ST1 and ST2
2 speech timers with speech playback interrupt function
-
WDT Watchdog
timer
I/O Control
I/O function control (input/output, pull-low, wake-up, etc)
2.2 Arithmetic Logic Unit (ALU)
The EM60000 series contain an 8-bit accumulator and an 8-bit arithmetic logic
unit that can perform 2’s-complement arithmetic operation, Boolean operation,
rotation, bit manipulation, data move, etc. There are several flags in the status
register to indicate the result of the operations. The following steps occur
during an ALU operation:
EM60000 Series User’s Manual
Architecture
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