I2C OPERATION DEFINTIONS
There are many control functions used to operate the I5216. Among them are the following.
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.
1. Host executes I2C START
Conventions used in I2C Data
S = START Condition
P = STOP Condition
2. Send Slave Address with R/W bit = “1” (Read) 81h.
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.
6. Slave responds with Upper Address byte of internal address
7. Host sends an ACK to Slave.
8. Wait for SCL to go high.
DATA = 8 bit data transfer
R = “1” in the R/W bit
= “0” in the R/W bit
A = ACK (Acknowledge)
N = No ACK
9. Slave responds with Lower Address byte of internal address
10. Host sends a NO ACK to Slave, then executes I2C STOP
= 7 bit Slave
The Box color indicates the
direction of data flow
= Host to Slave (Gray)
Note: The processor could have sent an I2C STOP after the Status
Word data transfer, and thus aborted the transfer of the Address bytes
= Slave to Host (White)
A graphical representation of this operation is found below. See the caption box above for more
S SLAVE ADDRESS R A DATA A DATA A DATA N P
High Addr. Low Addr.
Publication Release Date: November 30, 2001