- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
235
Communication format
The communication format supports packets up to 32 bytes. (The size varies depending on the command.)
The CXD3172AR receives a packet of data, analyzes it, and then performs control by executing a command.
Until this command is executed, no other commands may be received. For details regarding the command
processing time, see "Table 12.4-4 Communication Prohibited Period (Other Than for EEPROM Write)"
and ”Table 12.4-5 Communication Prohibited Period of EEPROM Write”.
Fig 12.4-3 Microcomputer Communication Format
Fig 12.4-4 DSP Response Timing
After the DSP receives a packet, it responds when it receives the next.
Flexible (max 32 Bytes)
SCK
XCS
SI
COMmand
SO
Start
Word
Hi-Z
Hi-Z
STatus
word
Byte1
Byte2
Byte3
Byte32
Start
Word
Byte4
Byte30
Byte31
Byte1
Byte2
Byte3
Byte4
Byte30
Byte31
Byte32
receive 1
1packet
SI
SO
respond1
External
microcomputer
-> 3172AR
<- 3172AR
DUMMY
By receiving dummy data,
response data can be
returned.
receive 2
receive 3
respond2
respond3
External
microcomputer