
DocID024597 Rev 5
491/1830
RM0351
Quad-SPI interface (QUADSPI)
500
17.6.2
QUADSPI device configuration register (QUADSPI_DCR)
Address offset: 0x0004
Reset value: 0x0000 0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
FSIZE
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
Res.
Res.
Res.
Res.
CSHT
Res.
Res.
Res.
Res.
Res.
Res.
Res.
CK-
MODE
rw
rw
rw
rw
Bits 31: 21 Reserved, must be kept at reset value.
Bits 20: 16
FSIZE[4:0]
: Flash memory size
This field defines the size of external memory using the following formula:
Number of bytes in Flash memory = 2
[FSIZE+1]
FSIZE+1 is effectively the number of address bits required to address the Flash
memory. The Flash memory capacity can be up to 4GB (addressed using 32 bits) in
indirect mode, but the addressable space in memory-mapped mode is limited to
256MB.
If DFM = 1, FSIZE indicates the total capacity of the two Flash memories together.
This field can be modified only when BUSY = 0.
Bits 15: 11 Reserved, must be kept at reset value.
Bits 10:8
CSHT[2:0]
: Chip select high time
CSHT+1 defines the minimum number of CLK cycles which the chip select (nCS) must
remain high between commands issued to the Flash memory.
0: nCS stays high for at least 1 cycle between Flash memory commands
1: nCS stays high for at least 2 cycles between Flash memory commands
...
7: nCS stays high for at least 8 cycles between Flash memory commands
This field can be modified only when BUSY = 0.
Bits 7: 1 Reserved, must be kept at reset value.
Bit 0
CKMODE
: Mode 0 / mode 3
This bit indicates the level that CLK takes between commands (when nCS = 1).
0: CLK must stay low while nCS is high (chip select released). This is referred to as
mode 0.
1: CLK must stay high while nCS is high (chip select released). This is referred to as
mode 3.
This field can be modified only when BUSY = 0.