r8a66154 Renesas Electronics Corporation., r8a66154 Datasheet - Page 3

• Manufacturer Part Number: r8a66154
• Description: 8-bit I/o Expander With Led Drive Function
• Manufacturer: Renesas Electronics Corporation.

R8A66154SP
DESCRIPTION OF OPERATION
OPERATION TIMING CHART
REJ03F0285-0100 Rev.1.00 Dec.08.2009
Page 3 of 7
(1) When power ON, the status of DO and D1~D8 terminals are not determined. These terminals are turn
(2) By the negative edge of /CS, the status of D1~D8 terminals is loaded on shift register 1.
(3) Synchronous to the negative edge of CLK, 8-bit loaded data is serial output from the DO terminal.
(4) Synchronous to the positive edge of CLK, 8-bit serial input data from DI is written into the shift register 2.
(5) The 9th and following shift clock pulse are ignored and the serial data input operation is stopped.
(6) By the positive edge of /CS, input data described in (4) is output to D1~D8 terminals.
(7) Shift register 1 loads the AND tie data of external parallel input data and latched data on parallel output
(8) If the /CS is changed from "L" to "H" before reaches the 8th bit of CLK, parallel output latch latches
(9) Input/output mode set to D1~D8 terminals are done by the serial input data to the DI terminal.
CLK
DO
CS
D1
D2
D8
DI
S
to high-impedance when "L" is input to the /S terminal.
And the DO terminal becomes high-impedance ("High-Z").
latch.
data which has been written on shift register 2 and output it to D1~D8 terminals. Serial data after this
since is ignored and the DO terminal becomes high-impedance.
Terminals which "H" is written are set to input, and "L" is written are set to output.
High-Z
High-Z
High-Z
High-Z
(1)
(2)
1
DO1
DI1
(3)
DI1
DI2
DI8
(4)
2
DO2
DI2
3
DO3
DI3
4
DO4
DI4
１Sequence
5
DO5
DI5
6
DO6
DI6
7
DO7
DI7
8
DO8
DI8
9
High-Z
(5)
(6)
DO1
DO2
DO8