7. I
2
C Interface > Mailboxes
162
Tsi578 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
C Slave Access Status Register”
are accessible by an
external host to examine the mailbox status.
2
C mailboxes.
Figure 33: I
2
C Mailbox Operation
The incoming and outgoing I
2
C mailbox registers are discussed further in the following sections.
EXI2C_MBOX_IN
Writes to Mailbox
0100.......000111
EXI2C_MBOX_IN
EXTERNAL
I
2
C MASTER
Flag Goes Up
EXI2C_ACC_STAT.IMB_FLAG
Host is Interrupted (IMB_FULL)
Host Reads Mailbox
Flag Goes Down
Polls Status Until Flag Down
PROCESSOR/
HOST
EXI2C_MBOX_IN
INCOMING MAIL
EXI2C_MBOX_OUT
Writes to Mailbox
0100.......000111
EXI2C_MBOX_OUT
EXTERNAL
I
2
C MASTER
Flag Goes Up
EXI2C_ACC_STAT.OMB_FLAG
Host is Interrupted (OMB_EMPTY)
Reads Mailbox
Flag Goes Down
Polls Status Until Flag Up
PROCESSOR/
HOST
EXI2C_MBOX_OUT
OUTGOING MAIL