FEDL2250DIGEST-09

OKI Semiconductor

ML2250 family

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2. Serial Interface

When selecting the serial interface, the I/O pins ÝÍ, ÉÎ, ÜÉ, DI, SCK, ÎÜ, and DO are used as input pins to

input various commands and data, and as output pins to read out the status of the commands and data.

The micro-computer interface becomes effective when ÝÍ pin is set to “L” level.

To input the commands and data, “L” level is input to ÝÍ and ÉÎ pins followed by, from MSB, to DI pin in

synchronization with the input clock signal at SCK pin. Data at DI pin is captured inside the device on the

rising or falling edge of the clock at SCK pin. And the command is executed on the rising edge of the ÉÎ pin.

The selection of rising/falling edge of SCK clock is determined by the input level of the SCK pin on the falling

edge of the ÝÍ pin. If the SCK pin on the falling edge of the ÝÍ pin is at “L” level, the DI pin data is captured

inside the device on the rising edge of SCK clock. Conversely, if the SCK pin on the falling edge of the ÝÍ pin

is at “H” level, then the DI pin data is captured on the falling edge of SCK clock.

Use the ÜÉ pin to input various data after having input the EXT or Flash I/F command. The data input method

is the same as to input data from the ÉÎ pin.

The selection of rising/falling edge of SCK clock is determined by the input level of the SCK pin on the falling

edge of the ÉÎ pin. If the SCK pin on the falling edge of the ÉÎ pin is at “L” level, the DI pin data is captured

inside the device on the rising edge of SCK clock. Conversely, if the SCK pin on the falling edge of the ÉÎ pin

is at “H” level, then the DI pin data is captured on the falling edge of SCK clock.

Use the ÜÉ pin to input various data after having input the EXT or Flash I/F command. The data input method

is the same as to input data from the ÉÎ pin.

Command and Data Input Timings

SCK Rising Edge Operation

D7 D6

D5

D4

D3

D2 D1

D0

CS

(I)

WR

, DW(I)

DI(I)

SCK(I)

SCK falling Edge Operation

D7 D6

D5

D4

D3

D2 D1

D0

CS

(I)

WR

, DW(I)

DI(I)

SCK(I)