em78p156n ELAN Microelectronics Corp, em78p156n Datasheet - Page 8

• Manufacturer Part Number: em78p156n
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

4. FUNCTION DESCRIPTION
This specification is subject to change without prior notice.
4.1 Operational Registers
Control
Oscillator/Timing
OSCI
1. R0 (Indirect Addressing Register)
2. R1 (Time Clock /Counter)
OSCO
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).
/RESET
or by the instruction cycle clock.
value.
• Increased by an external signal edge, which is defined by TE bit (CONT-4) through the TCC pin,
• 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
R6
IOC6
I/O
PORT 6
IOCA
RAM
R4
WDT timer
Prescaler
R1(TCC)
DATA & CONTROL BUS
Interrupt
Controller
TCC
Fig. 2 Function Block Diagram
/INT
P60//INT
P61
P62
P63
P64
P65
P66
P67
8
Instruction
Decoder
Instruction
Register
ROM
R5
IOC5
I/O
PORT 5
R2
R3
EM78P156N
OTP ROM
07.29.2004 (V1.2)
ALU
Stack
ACC
P50
P51
P52
P53