EM78156EAS EMC [ELAN Microelectronics Corp], EM78156EAS Datasheet - Page 8

• Manufacturer Part Number: EM78156EAS
• Description: 8-Bit Microcontroller with MASK ROM
• Manufacturer: EMC [ELAN Microelectronics Corp]

EM78156E
8-Bit Microcontroller with MASK ROM
4
4 •
Control
Oscillator/Timing
OSCI
OSCO
FUNCTION DESCRIPTION
4.1 Operational Registers
/RESET
R6
IOC6
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)
I/O
PORT 6
IOCA
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.
RAM
R4
WDT timer
Prescaler
R1(TCC)
DATA & CONTROL BUS
Fig. 2 Function Block Diagram
Interrupt
Controller
TCC
/INT
P60//INT
P61
P63
P66
P67
P62
P64
P65
(This specification is subject to change without further notice)
Instruction
Decoder
Instruction
Register
ROM
IOC5
R5
Product Specification (V1.3) 07.29.2004
I/O
PORT 5
R2
R3
ALU
Stack
ACC
P50
P51
P52
P53