3.3

Register descriptions

Detailed descriptions of each register can be found in TCG PC Client Specific Platform TPM Profile for [PTP 2.0

r1.05].

3.4

Additional information

•

The TPM implement a PIRQ but does not implement an SIRQ pin.

•

Any write operation to the TPM_ACCESS_x register with more than one field set to a ‘1’ is not accepted.

•

Interface capability:

–

TPM_STS_x.burstCount is dynamic.

–

Interrupt detection mode “Level low” is supported (other modes “Level high” and “Edge” are not

supported).

–

Interrupts localityChange and dataAvailable are supported (Interrupt stsValid and commandReady

are not supported).

•

Transaction size:

–

The TPM accepts transactions to offset 0x0024-0x0027 which are of lengths from 1 to 32 bytes

(legacy FIFO).

–

The TPM accepts transactions to offset 0x0081-0x0083 which are of lengths from 1 to 32 bytes

(extended FIFO).

•

Vendor and Device ID for the TPM

–

TPM_DID_VID_X = 0x0000104A; // DID = 0x0000 and VID = 0x104A (id of STMicroelectronics

defined by TCG)

•

Revision ID for the TPM

–

TPM_RID_X = 0xFFFFFF4E; // 0xFFFFFF = reserved

3.5

Recommendations

For optimized performance results, the use of an extended data FIFO with 32-byte burst is mandatory.

When the falling edge occurs on the SPI_CS signal, SPI_CLK must be at the low logic level as defined in

Figure 7. SPI slave timing diagram - SPI_CLK low (by default).

If the device does not show this behavior, add a 56 pF capacitor (example value) on the SPI_CS line to slow the

falling edge on SPI_NSS or SPI_CS.

3.6

Integration requirements

•

When the falling edge occurs on the SPI_CS signal, SPI_CLK must be at the low logic level as defined in

Figure 7. SPI slave timing diagram - SPI_CLK low (by default).

If the device does not show this behavior, add a 56 pF capacitor (example value) on the SPI_CS line to

slow the falling edge on SPI_NSS or SPI_CS.

•

The duration of TPM_HASH_DATA exceeds 250 µs if SHA384 and Dual bank management are

implemented.

•

In Windows 10 or 11, for using a 3072-bit RSA key, update the following, if it exists in the registry editor:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TPM]

“TimeoutCommandCreate”=dword:00493E0

ST33TPHF2XSPI

Register descriptions

DS14186 - Rev 1

page 10/35