em78p210n ELAN Microelectronics Corp, em78p210n Datasheet - Page 14

• Manufacturer Part Number: em78p210n
• Description: 8-bit Microcontroller With Otp Rom
• Manufacturer: ELAN Microelectronics Corp

EM78P210N
8-Bit Microcontroller with OTP ROM
8 •
6.2.3 R0 (Indirect Addressing Register)
R0 is not a physically implemented register. Its major function is to perform as an
indirect address pointer. Any instruction using R0 as a pointer, actually accesses the
data pointed by the RAM Select Register (R4).
6.2.4 R1 (Memory Switch Register)
Bits 7~2: not used, fixed to 0 all the time.
Bits 1~0: is used to select Banks 0 ~ 1 for R20~R3F and select Banks 0~3 for control
register.
See the table under Section 6.1 Registers Configuration for the data memory
configuration.
6.2.5 R2 (Program Counter) and Stack
R2 and hardware stacks are 11-bit wide. The structure is depicted in the table under
Section 6.1 Register Configuration.
Generates 2K×13 bits on-chip ROM addresses to the relative programming instruction
codes. One program page is 1024 words long.
The contents of R2 are all set to "0"s when a reset condition occurs.
Bit 7
“0”
A10
PAGE0 0000~03FF
PAGE1 0400~07FF
Bit 6
“0”
A9
RET
RETL
RETI
CALL
Figure 6-1 Program Counter Organization
~
Bit 5
“0”
Stack Level 2
Stack Level 3
Stack Level 4
Stack Level 5
Stack Level 6
Stack Level 7
Stack Level 8
Stack Level 1
A0
Bit 4
“0”
(This specification is subject to change without further notice)
Bit 3
“0”
Product Specification (V1.2) 04.22.2008
On-chip Program
Bit 2
Interrupt Vector
“0”
Reset Vector
Memory
Bit 1
BS1
7FFH
000H
008H
Bit 0
BS0