W55P241 Datasheet, PDF (5/32 Pages) List of Unclassifed Manufacturers – I/O device usable with many different microprocessors through SPI interface

W55P241
4. BLOCK DIAGRAM
WAKEUP
Timing
Generator
PBOPR0TA ⁸
I/O
(⁽P^PW^WM^M)⁾
BP00-BP07
DIS
/CS
CLK
DI
DO
SPI
Control
Logic
Read
Write
Control
Buffer
8-bit
Internal
Data Bus
P_BO_PR₁TB
8
I/O
BP10-BP17
8
PBOPR2TC
I/O
BP20-BP27
Figure 1 W55P241 Block Diagram
5. FUNCTIONAL DESCRIPTION
The W55P241 provides up to three bi-directional ports. Each bi-directional port has 8 pins (BP00~07,
BP10~17, or BP20~27) and each bi-directional pin can be configured as an output pin or input pin
independently. One dedicated wakeup pin forcibly releases the microcontroller from the standby mode.
When selected as an input pin, the state change on each pin can trigger interrupt request, if the
corresponding interrupt enabling bit is set. These three bi-directional ports, when programmed as an
output port, can sink at least 25-mA current in order to drive LED directly. With an embedded 256-level
output circuit, motor speed control and LED brightness are available in BP00~BP07.
5.1 SPI
SPI is a direct and simple interface that uses 4 pads (/CS, CLK, DI and DO) for data exchange
between master and slave. W55P241 operates in the slave mode and up to 2 W55P241 devices can
function simultaneously. The master identifies the slaves which are differentiated by the DIS pad.
Because W55P241 operates in mode 0 only, the CLK idle state is always “0”, “receive data” is always
latched at the rising edge of CLK, and “transmit data” is always changed (if at all) at the falling edge of
CLK. To control one SFR of W55P241, 16 bits of serial data must be transmitted from the master. 16
bits of serial data consist of 1 command byte and 1 data byte. Basically, 4 groups of commands are
defined and the IO port group suffices to generate all possible IO statuses. Users may use 3 other
speedup groups to minimize microcontroller load.
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