BS_Serial memory interface
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15.8.4 SMI_CR2
register
The SMI_CR2 (Control register 2) is a RW register which is able (together with coupled
SMI_CR1,
) to configure the behavior of SMI. The SMI_CR2 bit assignments
[03:02]
Not used
[01:00]
BE
2’h1
RW
Bank enable.
This is a 2 bit field where each bit is associated to a specific
external memory bank, specifically the LSB (bit [0]) refers to
bank0. Setting a bit, the relevant memory bank is enabled.
At power-on reset, all banks are disabled except bank0
(reset value 0x1) to allow booting from external memory, as
explained in
.
Note: If any AHB master makes a request on a disabled
bank (relevant bit cleared in BE field), an ERROR response
is sent back to AHB master. In contrast, write enable, read
status register and send commands are not sent if the bank
is disabled, without any error message.
Table 241.
SMI_CR1 register bit assignments (continued)
Bit
Name
Reset
value
Type
Description
Table 242.
SMI_CR2 register bit assignments
Bit
Name
Reset
value
Type
Description
[31:14]
Reserved
-
-
Read: undefined. Write: should be zero.
[13:12]
BS
2’h0
RW
Bank select.
This 2 bit field allows to select the external memory bank,
according to encoding:
2‘b00 = Bank0
2‘b01 = Bank1
2‘b10 = Not Implemented
2‘b11 = Not Implemented
Note: Only one bank can be accessed at a time, and the
BS value is latched at the beginning of transfer.
[11]
WEN
1’h0
RW
Write enable command.
Setting this bit, a write enable command is sent to the
memory bank selected by the BS field. The WEN bit is
then directly cleared by hardware as soon as the write
enable command has been successfully sent. A write of
1‘b0 has no effect.
Note: The WEN bit must be used in software mode to
send either a write or an erase command.