RMII Protocolos compatibles

Computadoras y servidores

Reduced Media Independent Interface

¿Qué es RMII?

RMII (Reduced Media Independent Interface) is a simplified versión of MII that reduces the pin count for 10/100 Mbps Ethernet MAC-to-PHY connections. RMII uses 2-bit-wide transmit and receive data paths (instead of 4-bit), sharing a single 50 MHz reference clock (instead of separate TX and RX clocks). This reduced pin count makes RMII popular in space-constrained designs and microcontrollers with limited pin availability. The trade-off is a higher clock frequency and tighter timing requirements. Engineers debugging embedded Ethernet implementations frequently encounter RMII interface issues related to clock distribution, timing alignment, and reference clock quality.

RMII Referencia rápida

type Parallel, reduced pin count
signals TXD[1:0], RXD[1:0], REF_CLK, etc.
max Speed 50 MHz (100 Mbps)
voltage Range 3.3V
standard IEEE 802.3u

Instrumentos Acute compatibles con RMII

Soluciones recomendadas

Recomendado para decodificación

TL4234B

TL4234B

Todos los productos compatibles

Decodificación de protocolo
Disparo por hardware
Emulador de protocolo

Serie LA4000

Serie MSO2000

Serie TravelLogic

¿Listo para analizar este protocolo?

Vea cómo los instrumentos Acute capturan y decodifican este protocolo en tiempo real. Solicite una demo o contacte a nuestro equipo.

¿Cómo analizar RMII con instrumentos Acute

1

Conecte su analizador lógico Acute a las señales RMII: TXD[1:0], RXD[1:0], REF_CLK, TX_EN y CRS_DV.

2

Conecte un cable de tierra a la referencia de tierra de la placa objetivo.

3

En el software Acute, seleccione el RMII protocol decoder y asigne cada señal al canal de entrada correspondiente.

4

Configure los parametros esperados de Ethernet speed (10 or 100 Mbps).

5

Capture y visualice los Ethernet frames for both transmit and receive directions, verifying frame integrity and timing.

Preguntas frecuentes

Que tasa de muestreo necesito para el análisis RMII ?
RMII uses a 50 MHz reference clock. Sample at a minimum of 200 MHz (4x the clock) for reliable decoding. A sample rate of 500 MHz or higher is recommended for accurate timing analysis of data setup and hold times, which are critical for diagnosing intermittent RMII link issues.
Por que mi enlace Ethernet RMII se cae intermitentemente?
Intermittent RMII link issues are frequently caused by reference clock quality problems — jitter, duty cycle distortion, or routing-induced skew between the clock and data signals. Capture the REF_CLK alongside the data signals and measure timing margins. Also verify that the CRS_DV signal is properly de-multiplexing carrier sense and receive data valid, as incorrect CRS_DV interpretation can cause frame reception failures.
Cuantos canales se necesitan para el análisis de RMII ?
Full bidirectional RMII analysis requires 7 channels: TXD[1:0], TX_EN, RXD[1:0], CRS_DV, and REF_CLK. For monitoring only one direction (transmit or receive), 4 channels are sufficient. If you also need to monitor MDIO management bus traffic alongside RMII, add 2 more channels for MDC and MDIO.

Protocolos relacionados

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