USB5534B Datasheet, PDF (38/73 Pages) Microchip Technology – 4-Port SS/HS USB Hub Controller

USB5534B
5.6.1.2 Configuration Register Read Example
The following example shows how to read the Charger Detection register to find out what type of charger the hub has
connected to:
1. Write data to the memory of the hub.
TABLE 5-16: EXAMPLE SMBUS WRITE COMMAND
Byte
Value
Comment
0
5Ah
Address plus write bit.
1
00h
Memory address 0000h.
2
00h
Memory address 0000h.
3
04h
Number of bytes to write to memory.
4
01h
Read Configuration Register.
5
01h
Reading one data bytes.
6
30h
BC Detect is in register 30E2h.
7
E2h
BC Detect is in register 30E2h.
2. Execute the Configuration Register Access command.
TABLE 5-17: CONFIGURATION REGISTER ACCESS COMMAND
Byte
Value
Comment
0
5Ah
Address plus write bit.
1
99h
Command 9937h.
2
37h
Command 9937h.
3
00h
Command Completion.
3. Read back data starting at memory offset 04h, which is where the Data byte starts.
TABLE 5-18: EXAMPLE SMBUS READ COMMAND
Byte
Value
Comments
0
5Ah
Address plus Write bit.
1
00h
Memory Address 0004h.
2
04h
Memory Address 0004h.
3
59h
Address plus Read bit.
4
80h
Device sends 128 bytes of data.
5
56h
Charging Downstream Port Detected.
Although the device can send out 128 bytes of memory data, it isn’t necessary to read the entire set, the SMBus Master
can send a stop at any time.
DS00001681C-page 38
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