# US 12,216,162 B2 · Performing scan data transfer inside multi-die package with serdes functionality

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- Number: US 12,216,162 B2
- Document ID: US12216162B2
- Status: Granted
- Kind: B2
- Application number: 18/364,568
- Filed: 2023-08-03
- Published: 2024-01-25
- Granted: 2025-02-04
- Earliest claimed: 2019-10-21
- Assignees: Advanced Micro Devices, Inc.
- Applicants: Advanced Micro Devices, Inc.
- Inventors: Ahmet Tokuz; Saurabh B. Upadhyay
- Web page: https://patentgrep.com/patent/US12216162B2

## CPC

- G01R 31/318583: {Design for test}
- G01R 31/3177: Testing of logic operation, e.g. by logic analysers
- G01R 31/318572: {Input/Output interfaces}
- G06F 11/2236: {to test CPU or processors}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A system for performing a scan test of a processor core includes a scan test module and a processor including a processor core and an input/output die, where the input/output die is coupled to the processor core. The scan test module transmits, in parallel to the input/output die, scan test input data. A serializer/deserializer module of the input/output die receives the input data, serializes the input data, and transmits the serialized input data to the processor core. A serializer/deserializer module of the processor core receives the serialized scan test input data, deserializes the input data, receives result data generated in dependence upon the input data, serializes the result data, and transmits the serialized result data to the input/output die. The input/output die serializer/deserializer module receives the result data, deserializes the result data, and provides the result data to the scan test module. Error detection can be carried out through redundancy.

## Claims

### Claim 1

An apparatus comprising:
a first die; and
a second die, wherein the second die is coupled to the first die through a plurality of direct coupled (DC) links and the second die is configured to:
serialize non-serialized test input data to produce serialized test input data; and
transmit the serialized test input data to the first die.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the second die is configured to encode the serialized test input data with data strobe encoding.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the first die is configured to:
receive the serialized test input data; and
deserialize the serialized test input data to produce deserialized test input data.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein the first die is further configured to:
provide the deserialized test input data to a device under test; and
receive result data generated by the device under test based on the deserialized test input data.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the first die is further configured to:
serialize the result data; and
transmit the serialized result data to the second die.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the first die is further configured to encode the serialized result data with data strobe encoding.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the second die is further configured to:
receive the serialized result data;
deserialize the serialized result data; and
provide the deserialized result data to a testing module.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the second die is further configured to hold, in a buffer, the serialized result data until expiration of a first predetermined period of time prior to deserializing the serialized result data.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein the second die is further configured to release, from the buffer, the serialized result data responsive to the expiration of the first time period.

### Claim 10 (depends on 5)

The apparatus of claim 5, wherein the first die is further configured to hold, in a buffer, the serialized test input data until expiration of a second predetermined period of time prior to deserializing the serialized test input data.

### Claim 11 (depends on 10)

The apparatus of claim 10, wherein the second die is further configured to release, from the buffer, the serialized test input data responsive to expiration of the second time period.

### Claim 12 (depends on 1)

The apparatus of claim 1, wherein the second die is further configured to receive the non-serialized test input data from a testing module.

### Claim 13 (depends on 1)

The apparatus of claim 1, wherein the first die comprises a processor die.

### Claim 14 (depends on 1)

The apparatus of claim 1, wherein the second die comprises an input/output (I/O) die.

### Claim 15

A method comprising:
serializing, by a first die coupled to a second die through a plurality of direct coupled links, non-serialized test input data to produce serialized test input data;
transmitting, by the second die, the serialized test input data to the first die.

### Claim 16 (depends on 15)

The method of claim 15, further comprising:
receiving, by the second die, the serialized test input data; and
deserializing, by the second die, the serialized test input data to produce deserialized test input data.

### Claim 17 (depends on 16)

The method of claim 16, further comprising:
providing, by the second die, the deserialized test input data to a device under test; and
receiving, by the second die, result data generated by the device under test based on the deserialized test input data.

### Claim 18 (depends on 17)

The method of claim 17, further comprising:
serializing, by the second die, the result data; and
transmitting, by the second die, the serialized result data to the first die.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
receiving, by the first die, the serialized result data;
deserializing, by the first die, the serialized result data; and
providing, by the first die, the deserialized result data to a testing module.

### Claim 20 (depends on 15)

The method of claim 15, wherein the first die comprises an input/output (I/O) die and the second die comprises a processor die.