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GD32E23x User Manual
43
Block
Name
Address
size(bytes)
.
.
.
.
.
.
.
.
.
Page 63
0x0800 FC00 - 0x0800 FFFF
1KB
Information Block
Boot Loader
0x1FFF EC00 - 0x1FFF F7FF
3KB
Option byte Block
Option byte
0x1FFF F800 - 0x1FFF F80F
16B
One-time program
Block
OTP bytes
0x1FFF_7000~0x1FFF_73FF
1KB
Note:
The Information Block stores the bootloader - this block cannot be programmed or
erased by user.
2.3.2.
Read operations
The flash can be addressed directly as a common memory space. Any instruction fetch and
the data access from the flash are through the AHB BUS from the CPU.
Wait state added:
Configure the WSCNT bits in the FMC_WS register correctly depend on the AHB clock
frequency. The relation between WSCNT and AHB clock frequency is shown in
The relation between WSCNT and AHB clock frequency
Table 2-2. The relation between WSCNT and AHB clock frequency
AHB clock frequency
WSCNT configured
<= 24MHz
0 (0 wait state added)
<= 48MHz
1 (1 wait state added)
<= 72MHz
2 (2 wait state added)
If system reset occurs, the AHB clock frequency is 8MHz and the WSCNT is 0.
Note:
1. If it is needed to increase the AHB clock frequency. First, refer to
between WSCNT and AHB clock frequency
, configure the WSCNT bits according to the
target AHB clock frequency. Then, increase the AHB clock frequency to the target frequency.
It is forbidden to increase the AHB clock frequency before configuring the WSCNT.
2. If it is needed to decrease the AHB clock frequency. First, decrease the target AHB clock
frequency. Then refer to
Table 2-2. The relation between WSCNT and AHB clock
, configure the WSCNT bits according the target AHB clock frequency. It is
forbidden to configure the WSCNT bits before decrease the AHB clock frequency.
Because the wait state is added, the read efficiency is very low (such as add 2 wait state
when 72MHz). In order to speed up the read access, there are some functions performed.