M38517F8FP Renesas Electronics America, M38517F8FP Datasheet - Page 52

• Manufacturer Part Number: M38517F8FP
• Description: MCU 8-Bit 740 CISC 32KB Flash 5V 42-Pin SSOP
• Manufacturer: Renesas Electronics America

Specifications of M38517F8FP

• Package: 42SSOP
• Family Name: 740
• Maximum Speed: 8 MHz
• Ram Size: 1 KB
• Program Memory Size: 32 KB
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 34
• Interface Type: I2C-BUS
• On-chip Adc: 5-chx10-bit
• Operating Temperature: -20 to 85 °C
• Number Of Timers: 4

3851 Group
(1) CPU Rewrite Mode
In CPU rewrite mode, the internal flash memory can be operated
on (read, program, or erase) under control of the Central Process-
ing Unit (CPU).
In CPU rewrite mode, only the User ROM area shown in Figure 57
can be rewritten; the Boot ROM area cannot be rewritten. Make
sure the program and block erase commands are issued for only
the User ROM area and each block area.
The control program for CPU rewrite mode can be stored in either
User ROM or Boot ROM area. In the CPU rewrite mode, because
the flash memory cannot be read from the CPU, the rewrite con-
trol program must be transferred to internal RAM area to be
executed before it can be executed.
Fig. 57 Block diagram of built-in flash memory
Rev.1.01
P r o d u c t n a m e
M 3 8 5 1 7 F 8
Oct 15, 2003
(Built-in 24 KB or more ROM)
F l a s h m e m o r y
s t a r t a d d r e s s
80 0 0
1 6
page 50 of 89
P a r a l l e l I / O m o d e
C P U r e w r i t e m o d e , s t a n d a r d s e r i a l I / O m o d e
8 0 0 0
FFFF
8000
F F F F
1 6
16
16
User area / Boot area selection bit = 0
1 6
U s e r R O M a r e a
U s e r R O M a r e a
BSEL = 0
Block 1 : 32 kbyte
B l o c k 1 : 3 2 k b y t e
Microcomputer Mode and Boot Mode
The control program for CPU rewrite mode must be written into
the User ROM or Boot ROM area in parallel I/O mode beforehand.
(If the control program is written into the Boot ROM area, the stan-
dard serial I/O mode becomes unusable.)
See Figure 57 for details about the Boot ROM area.
Normal microcomputer mode is entered when the microcomputer
is reset with pulling CNV
operating using the control program in the User ROM area.
When the microcomputer is reset by pulling the P4
the CNVss pin high, the CPU starts operating using the control
program in the Boot ROM area (program start address is FFFC
FFFD
Block Address
Block addresses refer to the maximum address of each block.
These addresses are used in the block erase command. In case
of the M38517F8, it has only one block.
16
N o t e s 1 : T h e B o o t R O M a r e a c a n b e r e w r i t t e n i n o n l y p a r a l l e l
FFFF
F F F F
F 0 0 0
F 0 0 0
fixation). This mode is called the “Boot” mode.
1 6
1 6
16
1 6
2 : T o s p e c i f y a b l o c k , u s e t h e m a x i m u m a d d r e s s i n t h e b l o c k .
i n p u t / o u t p u t m o d e . ( A c c e s s t o a n y o t h e r a r e a s i s i n h i b i t e d . )
User area / Boot area selection bit = 1
B o o t R O M a r e a
B o o t R O M a r e a
BSEL = 1
4 kb y t e
4 kb y t e
SS
pin low. In this case, the CPU starts
1
/INT
0
pin high,
16
,