---
title: "W5500 PHY Operation Mode Select - Hardware vs Software"
url: "https://maker.wiznet.io/forum/12856"
markdown_url: "https://maker.wiznet.io/forum/12856/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "acpie360"
created: "2018-04-16T14:33:59+09:00"
last_activity: "2018-04-19T23:43:48+09:00"
language: "en"
views: 1013
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 PHY Operation Mode Select - Hardware vs Software

## Question

Asked by acpie360 on 2018-04-16 in Ethernet Chips.

My understanding is that the PHY operation mode can be set by either PMODE2 - PMODE0 (pin #43 - #45) or the software
/**
* @ingroup DATA_TYPE
* It configures PHY configuration when CW_SET PHYCONF or CW_GET_PHYCONF in W5500,
* and it indicates the real PHY status configured by HW or SW in all WIZCHIP. \n
* Valid only in W5500.
*/
typedef struct wiz_PhyConf_t
{
uint8_t by; ///< set by @ref PHY_CONFBY_HW or @ref PHY_CONFBY_SW
uint8_t mode; ///< set by @ref PHY_MODE_MANUAL or @ref PHY_MODE_AUTONEGO
uint8_t speed; ///< set by @ref PHY_SPEED_10 or @ref PHY_SPEED_100
uint8_t duplex; ///< set by @ref PHY_DUPLEX_HALF @ref PHY_DUPLEX_FULL
//uint8_t power; ///< set by @ref PHY_POWER_NORM or @ref PHY_POWER_DOWN
//uint8_t link; ///< Valid only in CW_GET_PHYSTATUS. set by @ref PHY_LINK_ON or PHY_DUPLEX_OFF
} wiz_PhyConf;

Since the software can override the hardware, why do we even have these PMODEx pins at the first place? Is there anything the hardware can do but the software can’t?

## Replies

### Reply 1 by justinkim, 2018-04-19

Hi acpie360

The two methods are simply the difference between software and hardware.

thank you

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Source: https://maker.wiznet.io/forum/12856