EM78156E
8-Bit Microcontroller with MASK ROM
4 FUNCTION DESCRIPTION
OSCO
/RESET
OSCI
TCC /INT
WDT timer
Prescaler
Oscillator/Timing
Control
ROM
R2
Stack
ALU
IOCA
RAM
Interrupt
Controller
Instruction
Register
R3
R1(TCC)
R4
Instruction
Decoder
ACC
DATA & CONTROL BUS
P60//INT
P61
P62
IOC6
R6
IOC5
R5
P50
I/O
PORT 6
I/O
PORT 5
P63
P64
P65
P66
P67
P51
P52
P53
Fig. 2 Function Block Diagram
4.1 Operational Registers
4.1.1 R0 (Indirect Addressing Register)
R0 is not a physically implemented register. Its major function is to perform as an
indirect addressing pointer. Any instruction using R0 as a pointer actually accesses
data pointed by the RAM Select Register (R4).
4.1.2 R1 (Time Clock /Counter)
ꢀ
Increased by an external signal edge which is defined by TE bit (CONT-4) through
the TCC pin, or by the instruction cycle clock.
ꢀ
ꢀ
ꢀ
ꢀ
Writable and readable as any other registers.
Defined by resetting PAB(CONT-3).
The prescaler is assigned to TCC, if the PAB bit (CONT-3) is reset.
The contents of the prescaler counter will be cleared only when TCC register is
written with a value.
4 •
Product Specification (V1.3) 07.29.2004
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
