ht82m73e Holtek Semiconductor Inc., ht82m73e Datasheet - Page 26

• Manufacturer Part Number: ht82m73e
• Description: 2.4ghz Mouse Tx 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

SPI Serial Interface
The device includes single SPI Serial Interfaces. The
SPI interface is a full duplex serial data link, originally
designed by Motorola, which allows multiple devices
connected to the same SPI bus to communicate with
each other. The devices communicate using a mas-
ter/slave technique where only the single master device
can initiate a data transfer. A simple four line signal bus
is used for all communication.
SPI Interface Communication
Four lines are used for SPI communication known as
SDI - Serial Data Input, SDO - Serial Data Output, SCK -
Rev. 1.00
SPI Block Diagram
26
Serial Clock and SCS - Slave Select. Note that the con-
dition of the Slave Select line is conditioned by the
CSEN bit in the SBCR control register. If the CSEN bit is
high then the SCS line is active while if the bit is low then
the SCS line will be in a floating condition. The following
timing diagram depicts the basic timing protocol of the
SPI bus.
SPI Registers
There are two registers associated with the SPI Inter-
face. These are the SBCR register which is the control
register and the SBDR which is the data register. The
HT82M73E
May 14, 2008