CS89712-CB View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS89712-CB

High-Performance, Low-Power System-on-Chip with 10BASE-T Ethernet Controller

Cirrus Logic 

CS89712

4.1.6 Loopback/Collision Diagnostic Tests

Internal and external Loopback and Collision tests

can be used to verify the CS89712’s Ethernet port

functionality. Internal tests allow the major digital

functions to be tested, independent of the analog

functions. During these tests, the Manchester en-

coder is connected to the decoder. All digital cir-

cuits are operational, and the transmitter and

receiver are disabled. External test modes allow the

complete chip to be tested without connecting it di-

rectly to an Ethernet network.

4.1.7 Loopback Tests

During Loopback tests, the internal Carrier Sense

(CRS) signal, used to detect collisions, is ignored,

allowing packet reception during transmission.

4.1.8 10BASE-T Loopback/Collision Tests

10BASE-T Loopback and Collision Tests are con-

trolled by two bits in the Test Control register:

FDX (Register 19, TestCTL, Bit E) and ENDE-

Cloop (Register 19, TestCTL, Bit 9). Table 88 de-

scribes these tests.

4.2 In-Circuit Emulation

4.2.1 Introduction

EmbeddedICE™ is an extension to the architecture

of the ARM family of processors, and provides the

ability to debug cores that are deeply embedded

into systems. It consists of three parts:

1) A set of extensions to the ARM core

2) The EmbeddedICE macrocell, which provides

external access to the extensions

Test Mode

10BASE-T Internal

Loopback

10BASE-T Internal

Collision

FDX

1

0

10BASE-T

1

External Loop-

back

10BASE-T

0

External Collision

ENDECloop

1

1

0

0

DisableLT

1

1

0

0

Description of Test

Transmit a frame and verify that the frame is

received without error.

Transmit frames and verify that collisions are

detected and that the internal counters function

properly. After 16 collisions, verify that 16coll

(Register 8, TxEvent, Bit F) is set.

Connect TXD+ to RXD+ and TXD- to RXD-.

Transmit a frame and verify that the frame is

received without error.

Connect TXD+ to RXD+ and TXD- to RXD-.

Transmit frames and verify that collisions are

detected and that internal counters function

properly. After 16 collisions, verify that 16coll

(Register 8, TxEvent, Bit F) is set.

Table 88. 10BASE-T Loopback and Collision Tests

138

DS502PP2

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