Access Area; Fig. 2.2.1 Access Area Of M37221M4-Xxxsp And M37221M6-Xxxsp/Fp - Renesas 7200 Series User Manual

FUNCTIONAL DESCRIPTION

2.2 Access area

2.2 Access area
The ROM, RAM and various I/O control registers are assigned within the same memory area. Therefore, the
same instructions are used for data transfers and arithmetic operations without making any distinction
between memory and I/O.
Since the program counter is a 16-bit register, 64 K-byte memory area can be accessed: from addresses
as 0000 to FFFF .
16 16
The first 256 bytes of the 64 K-byte memory area are called the "zero page" and the last 256 bytes are
called the "special page." These areas can be accessed with only 2 bytes by using each special addressing
mode.
M37220M3-XXXSP/FP
Refer to "CHAPTER 4. M37220M3-XXXSP/FP."
RAM RAM
(384 bytes) (320 bytes)
for for
M37221M6 M37221M4
CRT display RAM
(96 bytes)
(See note)
ROM ROM
(24 K bytes) (16 K bytes)
for for
M37221M6 M37221M4

Fig. 2.2.1 Access area of M37221M4-XXXSP and M37221M6-XXXSP/FP

2-8
0000
16
Internal RAM
00C0 SFR area
16
Special function register
(Refer to Figures 2. 3. 3 and 2. 3. 4)
00FF
16
Internal RAM
017F
16
01BF
16
Not used
0600
16
RAM
for display
06B7
16
Not used
A000
16
C000
16
Internal ROM
FF00
16
FFDE
16
Interrupt vector area
FFFF
16
7220 Group User's Manual
10000
CRT display ROM
(8 K bytes)
Zero page
11FFF
: Internal ROM area for
program counter
Special page
1FFFF
Note: Refer to Table 2.11.4 Contents of CRT display RAM.
16
ROM
for display
16
Not used
16