GMS77C1001 Datasheet, PDF (21/44 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS77C1000/GMS77C1001
9. MEMORY
The GMS77C1000/1001 has separate memory maps for
program memory and data memory. Program memory can
only be read, not written to. It can be up to 1K words of
program memory. Data memory can be read and written to
32 bytes including special function registers.
9.1 Program Memory
The program memory is organized as 0.5K, 12-bit wide
words(GMS77C1000) and 1K, 12-bit wide
words(GMS77C1001). The program memory words are
addressed sequentially by a program counter. Increment-
ing at location 1FF_H(GMS77C1000) or 3FF_H
(GMS77C1001) will cause a wrap around to 000_H.
Figure 9-1 and Figure 9-2 show a map of program memo-
ry. After reset, CPU begins execution from reset vector
which is stored in address(1FF_H: GMS77C1000, 3FF_H:
GMS77C1001).
PC<8:0>
000_H
0FF_H
100_H
1FF_H
200_H
2FF_H
300_H
3FF_H
PC<9:0>
Stack Level 1
Stack Level 2
On-chip
Program
Memory
(Page 0)
On-chip
Program
Memory
(Page 1)
Reset Vector
000_H
0FF_H
100_H
Stack Level 1
Stack Level 2
On-chip
Program
Memory
1FF_H
Reset Vector
FIGURE 9-1 GMS77C1000 PROGRAM MEMORY MAP
AND STACK
FIGURE 9-2 GMS77C1001 PROGRAM MEMORY MAP
AND STACK
9.2 Data Memory
The data memory consists of 25 bytes of RAM and seven
special function registers. The data memory locations are
addressed directly or indirectly by using FSR.
Figure 9-3 shows a map of data memory. The special func-
tion registers are mapped into the data memory..
File Address
00_H
INDF
01_H
TMR0
02_H
PCL
03_H
STATUS
04_H
FSR
05_H
RA
06_H
RB
00_H
06_H
07_H
0F_H
10_H
1F_H
Special
Function
Registers
DATA
MEMORY
(SRAM)
DATA
MEMORY
(SRAM)
FIGURE 9-3 GMS77C1000/1 DATA MEMORY MAP
18
July. 2001 Ver. 1.1