Electronics America Computer Hardware User Manual

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Chapter 10 Clock Synchronous Serial Interface
10
Fig. 10-28 Sending a Command from Master Device to Slave Device
Program processing
Hardware operation
Program processing
SCK pin
12345678
SB0 pin
C7
Hardware operation
C6 C5 C4 C3 C2
C1
C0 ACK READY
Command
Master device processing (transmitter)
Transfer line Slave device processing (receiver)
Interrupt handling (preparation for next serial transfer)
Serial transmission
Generate
INTCSI
Serial reception
Generate
INTCSI
Output BUSY
Clear BUSY
BUSY
Set CMDT
Write to SIO
Set ACKD
Stop SCK
Read
SIO
Analyze command
Set ACKT
Clear BUSY
Set CMDD
Output ACK
Remark This timing is valid only under the following conditions:
• The master is only allowed to transmit a command. • The slave is only allowed to receive a command.
ACKE is set to 0 and BSYE is set to 1.