ht82k73e Holtek Semiconductor Inc., ht82k73e Datasheet - Page 28

• Manufacturer Part Number: ht82k73e
• Description: 2.4ghz Keyboard Tx 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

SPI Serial Interface
The device includes two SPI Serial Interfaces. The SPI
interface is a full duplex serial data link, originally de-
signed by Motorola, which allows multiple devices con-
nected to the same SPI bus to communicate with each
other. The devices communicate using a master/slave
technique where only the single master device can initi-
ate 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
28
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
HT82K73E
April 16, 2008