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4.3. Flash Memory
The Flash memory is used to store application programs and data. Address 0x0 in the Flash area is
defined as the vector table base address by default, therefore a vector table must be located beginning
from this address. For more information on the vector table, refer to "Vector Table" in the "Interrupt"
chapter.
4.3.1. Flash Memory Pin
Table 4.3.1.1 shows the Flash memory pin.
Pin name
VPP
For the VPP voltage, refer to "Recommended Operating Conditions, Flash programming voltage
VPP" in the "Electrical Characteristics" chapter.
Note:
Always leave the V
pin open except when programming the Flash memory.
PP
4.3.2. Flash Bus Access Cycle Setting
There is a limit of frequency to access the Flash memory with no wait cycle, therefore, the number of
bus access cycles for reading must be changed according to the system clock frequency. The number of
bus access cycles for reading can be configured using the FLASHCWAIT.RDWAIT[1:0] bits. Select a
setting for higher frequency than the system clock.
4.3.3. Flash Programming
The Flash memory supports on-board programming, so it can be programmed using a flash loader. The
V
voltage can be supplied from either an external power supply or the internal voltage booster.
PP
Choose the flash loader ac- cording to the V
Notes:
•
When the V
voltage is supplied externally, 2.4 V or more V
PP
•
When the V
voltage is generated internally, 2.7 V or more V
PP
4.4. RAM
The RAM can be used to execute the instruction codes copied from another memory as well as storing
variables or other data. This allows higher speed processing and lower power consumption than Flash
memory.
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
Table 4.3.1.1 Flash Memory Pin
I/O
Initial status
P
–
power supply to be used.
PP
Seiko Epson Corporation
Function
Flash programming power supply
voltage is required.
DD
voltage is required.
DD
4-3
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