I5216 SERIES
Advanced Information
PRELIMINARY
I2C OPERATION DEFINTIONS
There are many control functions used to operate the I5216. Among them are the following.
Conventions used in I2C Data
Transfer Diagrams
READ STATUS COMMAND: The read status command is a read
request from the Host processor to the I5216 without delivering a
Command Byte. The Host supplies all of the clocks (SCL). In each
case, the entity sending the data drives the data line (SDA). The Read
Status Command is executed by the following I2C sequence.
S
P
= START Condition
= STOP Condition
1. Host executes I2C START
2. Send Slave Address with R/W bit = “1” (Read) 81h.
DATA
R
= 8 bit data transfer
= “1” in the R/W bit
3. Slave responds back to Host an Acknowledge (ACK), followed
by 8 bit Status word.
4. Host sends an Acknowledge (ACK) to Slave.
5. Wait for SCL to go HIGH.
W
= “0” in the R/W bit
6. Slave responds with Upper Address byte of internal address
register.
A
N
= ACK (Acknowledge)
7. Host sends an ACK to Slave.
8. Wait for SCL to go high.
= No ACK
9. Slave responds with Lower Address byte of internal address
register.
SLAVE ADDRESS
= 7 bit Slave
Address
10. Host sends a NO ACK to Slave, then executes I2C STOP
The Box color indicates the
direction of data flow
= Host to Slave (Gray)
= Slave to Host (White)
Note: The processor could have sent an I2C STOP after the Status
Word data transfer, and thus aborted the transfer of the Address bytes
A graphical representation of this operation is found below. See the caption box above for more
explanation.
S
SLAVE ADDRESS
R
A
DATA
A
DATA
A
DATA
N
P
Status
High
Addr.
Low
Addr.
Publication Release Date: November 30, 2001
Revision A1
-19
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