4/29/2020
Loongson 3A3000 / 3B3000 Processor User Manual
97
116
Bit field
Bit field name
Bit width access
description
7: 6
cnt
2
RW
Send an interrupt request signal after how many bytes are transferred
00 – 1 byte
01-2 bytes
10-3 bytes
11-3 bytes
5: 2
Rese
4
RW
Keep
1: 0
sp
2
RW
Set the frequency division ratio together with Sp
Frequency division factor:
spre
spr
00
00
00
01
00
10
00
11
01
00
01
01
01
10
01
11
10
00
10
01
10
10
10
11
Frequency division factor
2
4
16
32
8
64 128 256 512 1024 2048 4096
11.4.5
Parameter control register (SFC_PARAM)
Chinese name:
SPI Flash parameter control register
Register bit width: [7: 0]
Offset:
0x04
Reset value:
0x21
Bit field
Bit field name
Bit width
access
description
7: 4
clk_div
4
RW
Clock frequency division number selection (frequency division coefficient is the same as {spre, spr} combination)
3
dual_io
1
RW
Use dual I / O mode with higher priority than fast read mode
2
fast_read
1
RW
Use quick read mode
1
burst_en
1
RW
spi flash supports continuous address read mode
0
memory_en
1
RW
spi flash read enable, when invalid, csn [0] can be controlled by software.
11.4.6
Chip Select Control Register (SFC_SOFTCS)
Chinese name:
SPI Flash Chip Select Control Register
Register bit width: [7: 0]
Offset:
0x05
Reset value:
0x00
Page 121
Godson 3A3000 / 3B3000 Processor User Manual • Volume 1
Bit field
Bit field name
Bit width
access
description
7: 4
csn
4
RW
csn pin output value
3: 0
csen
4
RW
When it is 1, the corresponding cs line is controlled by 7: 4 bits
11.4.7
Timing control register (SFC_TIMING)
Chinese name:
SPI Flash timing control register
Register bit width: [7: 0]
Offset:
0x06
Reset value:
0x03
Bit field
Bit field name
Bit width
access
description
7: 2
Reserved
6
RW
Keep