Datasheet

MCP2221
DS20005292A-page 24  2014 Microchip Technology Inc.
3.1.1.1 Responses
TABLE 3-2: RESPONSE 1 STRUCTURE
Byte
Index
Function Description Value Effect
0 0x10 Status/Set Parameters – command code echo
1 0x00 Command completed successfully.
2 Cancel transfer 0x00 No special operation (i.e., Cancel current I
2
C/SMBus
transfer)
0x10 The current I
2
C/SMBus transfer was marked for cancella-
tion. The actual I
2
C/SMBus transfer cancellation and bus
release will need some time (a few hundreds of microsec-
onds, depending on the communication speed, initially
chosen for the canceled transfer)
0x11 The I
2
C engine (inside MCP2221) was already in Idle
mode. The cancellation command had no effect
30x00No Set I
2
C/SMBus communication speed was issued.
0x20 The new I
2
C/SMBus communication speed is now
considered.
0x21 The I
2
C/SMBus communication speed was not set
(e.g., I
2
C transfer in progress).
4 The divider
value given
at the same
index in the
command
field
Only in the case when the code for establishing a new
communication speed is given at Byte Index 3.
0x00 When the communication speed is not being set
5-7 Don’t care Any value
8 Internal I
2
C state machine state
value
9 Lower byte (16-bit value) of the
requested I
2
C transfer length
10 Higher byte (16-bit value) of the
requested I
2
C transfer length
11 Lower byte (16-bit value) of the
already transferred (through I
2
C)
number of bytes
12 Higher byte (16-bit value) of the
already transferred (through I
2
C)
number of bytes
13 Internal I
2
C data buffer counter
14 Current I
2
C communication
speed divider value
15 Current I
2
C Timeout value
16 Lower byte (16-bit value) of the
I
2
C address being used
17 Higher byte (16-bit value) of the
I
2
C address being used
18-21 Don’t care Any value
22 SCL line value –
as read from the pin