EM78P159N
8-Bit Microcontrollerwith OTP ROM
4 Function Description
OSCO
OSCI /RESET
Oscillator/Timing
Control
WDT timer TCC /INT
Prescaler
IOCA
RAM
Interrupt
Controller
R4
R1(TCC)
ROM
Instruction
Register
Instruction
Decoder
R2
Stack
ALU
R3
ACC
DATA & CONTROL BUS
P60//INT
P61
P50
P51
IOC6
R6
I/O
PORT 6
P62
P63
IOC5 I/O
P64
PORT 5
P65
R5
P52
P53
P54
P55
P66
P56
P67
Figure 4-1 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.
6•
Product Specification (V1.0) 03.10.2006
(This specification is subject to change without further notice)