SLVUC05A November 2020 – July 2022 TPS25750
The PD controller will transmit Source Capabilities that are written to this register without verifying them (besides limiting current see below). The user is responsible to write this register correctly per the USB PD requirements. The PD controller will only use the first TXSourceNumPDOs PDO's, the host may write multiple PDO's during configuration then dynamically write TXSourceNumPDOs to change which PDO's are advertised. If this register is changed, the host must subsequently issue the 4CC command 'SSrC'. This will cause the PD controller to re-load this TX Source Capabilities register.
The PD controller will read the capabilities of the cable and limit the maximum current in each PDO to respect the cable's VBUS Current Handling Capability.
Address | Name | Access | Length | Unique Per Port | Power-Up Default |
---|---|---|---|---|---|
0x32 | TX_SOURCE_CAPS | RW | 31 | yes | Initialized by Application Configuration |
Bits | Name | Description | |
---|---|---|---|
Bytes 28-31: PDO #7 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO7 | Seventh Source Capabilities PDO contents. See Table 2-23. | |
Bytes 24-27: PDO #6 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO6 | Sixth Source Capabilities PDO contents. See Table 2-23. | |
Bytes 20-23: PDO #5 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO5 | Fifth Source Capabilities PDO contents. See Table 2-23. | |
Bytes 16-19: PDO #4 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO4 | Fourth Source Capabilities PDO contents. See Table 2-23. | |
Bytes 12-15: PDO #3 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO3 | Third Source Capabilities PDO contents. See Table 2-23. | |
Bytes 8-11: PDO #2 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO2 | Second Source Capabilities PDO contents. See Table 2-23. | |
Bytes 4-7: PDO #1 (treated as a 32-bit little endian value) | |||
31:0 | TXSourcePDO1 | First Source Capabilities PDO contents. See Table 2-22. | |
Bytes 2-3: Power path configuration for each PDO. | |||
15:14 | Reserved | ||
13:12 | PowerPathForPDO7 | Configures which PP to use for PDO7. Same format as PowerPathForPDO2. | |
11:10 | PowerPathForPDO6 | Configures which PP to use for PDO6. Same format as PowerPathForPDO2. | |
9:8 | PowerPathForPDO5 | Configures which PP to use for PDO5. Same format as PowerPathForPDO2. | |
7:6 | PowerPathForPDO4 | Configures which PP to use for PDO4. Same format as PowerPathForPDO2. | |
5:4 | PowerPathForPDO3 | Configures which PP to use for PDO3. Same format as PowerPathForPDO2. | |
3:2 | PowerPathForPDO2 | Configures which PP to use for PDO2. | |
00b | Reserved\. | ||
01b | Reserved. | ||
10b | PP_EXT1 is used for this PDO. | ||
1:0 | PowerPathForPDO1 | Configures which PP to use for PDO1. | |
00b | PP_5V1 is used for this PDO. | ||
10b | PP_EXT1 is used for this PDO. | ||
Byte 1: Header | |||
7:3 | Reserved | ||
2:0 | numValidPDOs | Number of valid PDOs in this register. Each PDO is 4 bytes (max of 7). |
The PDO's in this register follow the definition in the USB PD specification. It is reproduced here for convenience, but for more details on each field refer to the USB PD specification.
Bits(s) | Description |
---|---|
31:30 | Supply Type, this shall always be set to 00b (Fixed Supply). |
29 | Dual-Role Power, this is overridden by the logical OR of the ProcessSwapToSink, ProcessSwapToSource, InitiateSwapToSink, and InitiateSwapToSource fields in the PORT_CONTRL register. |
28 | USB Suspend Supported. |
27:26 | Reserved |
25 | Dual-Role Data, this is overridden by the logical OR of the ProcessSwapToUFP, ProcessSwapToDFP, InitiateSwapToUFP, and InitiateSwapToDFP fields in the PORT_CONTRL register. |
24 | Unchunked Extended Messages supported. |
23:22 | Reserved. |
21:20 | Peak Current. |
19:10 | Voltage. |
9:0 | Maximum Current. |
Bits(s) | Description | ||
---|---|---|---|
Fixed Supply | Variable Supply | Battery Supply | |
31:30 | 00b | 01b | 10b |
29:20 | Reserved. | Maximum Voltage | Maximum Voltage |
19:10 | Voltage | Minimum Voltage | Minimum Voltage |
9:0 | Maximum Current | Maximum Current | Maximum Allowable Power |