Adding TPM transactions over SPI record

spi/tpm/README.md

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+# TPM transactions over SPI
+
+This is an example capture of TPM 2.0 transactions over SPI.
+
+The logic analyzer used to capture this signal was a DSLogic Pro.
+
+## Logic analyzer setup
+
+The logic analyzer used was a DSLogic Pro (at 250MHz):
+
+  Probe       SPI connector
+  -------------------------------------
+
+  1 (black) ->   CLK
+
+  2 (brown) ->  CS
+
+  3 (red)   ->    MOSI
+
+  4 (orange) ->  MISO
+
+
+## Capture (tpm_spi.sr)
+
+PulseView GUI was used to perform the capture.
+Here is the detail of the configuration:
+
+### SPI decoder configuration
+
+CS#: CS (Probe 2)
+
+MOSI: MOSI (Probe 3)
+
+CLK: CLK (Probe 1)
+
+MISO: MISO (Probe 4)
+
+
+CS# Polarity: Active low 
+
+Clock polarity: 0
+
+Clock phase: 0
+
+Bit order: msb-first
+
+Word size: 8
+
+### SPI TPM stack decoder configuration
+
+Stack Decoder: SPI TPM
+
+TPM Wait transfer Mask: 0x00
+
+## Output 
+
+TPM transactions are shown on the `TPM transactions` label.
+
+If the BitLocker Volume Master Key (VMK) is found, it should show it through the `BitLocker Volume Master Key` label.