Datasheet

MCP2221
DS20005292A-page 44  2014 Microchip Technology Inc.
3.1.10 I
2
C READ DATA – GET I2C DATA
This command is used to read back the data from the
I
2
C Slave device (its address and speed are specified
by the STATUS/SET Parameters command).
3.1.10.1 Responses
TABLE 3-30: COMMAND STRUCTURE
Byte
Index
Value Effect
00x40
I
2
C Read Data – Get I
2
C Data – command code
1 0x00 Requested I
2
C transfer length – 16-bit value – low byte
2 0x03 Requested I
2
C transfer length – 16-bit value – high byte
3-63 Don’t
care
TABLE 3-31: RESPONSE 1 STRUCTURE
Byte
Index
Value Effect
00x40
I
2
C Read Data – Get I
2
C Data – command code echo
1 0x00 Command completed successfully
0x41 Error reading the I
2
C slave data from the I
2
C engine
2 0x03 Internal I
2
C Engine state (at the moment the command was issued) – useful for monitoring the I
2
C
Engine’s status
3 0-60 The number of read-back data bytes to follow in this packet: from 0 to a maximum of 60 bytes of
read-back bytes
127 This value is signaled when an error has occurred and the following data should not be taken into
account
4-63 User Data or Don’t care