2-Port SS/HS USB Hub Controller

Datasheet

SMSC USB5532B

21

Revision 1.2 (05-31-13)

DATASHEET

5.1.4.3

COMMAND ONLY PROGRAM EXAMPLE

To perform a single byte command such as the following:

- WRDI

- WREN

- EWSR

- CHIP_ERASE

- EBSY

- DBSY

The device writes the opcode into the first byte of the SPI_CMD_BUF and the SPI_CMD_LEN is set

to one. The device first drops SPI_CE, then 8 bits of the command are clocked out on the SPI_DO pin.

The SPI_DI is not used in this example.

Figure 5.8 SPI Command Only Sequence

5.1.4.4

JEDEC-ID READ EXAMPLE

To perform a JEDEC-ID command, the device writes 0x9F into the first byte of the SPI_CMD_BUF and

the length of the transfer is 4 bytes. The device first drops SPI_CE_N, then 8 bits of the command are

clocked out, followed by the 24 bits of dummy bytes (due to the length being set to 4) on the SPI_DO

pin. When the transfer is complete, the SPI_CE_N goes high. After the first byte, the data on SPI_DI

SPI_CEN

SPI_CLK

12 3 4

05

7

6

SPI_DO

SPI_DI

Command

MSB

HIGH IMPEDANCE