--- title: "WIZ750SR Stuck in AT Mode" url: "https://maker.wiznet.io/forum/15195" markdown_url: "https://maker.wiznet.io/forum/15195/md" type: "Forum topic" category: "Serial-to-Ethernet & ConfigTool" author: "Fife" created: "2024-04-12T04:13:58+09:00" last_activity: "2025-01-24T18:23:42+09:00" language: "en" views: 153 replies: 5 source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)" --- # WIZ750SR Stuck in AT Mode ## Question Asked by Fife on 2024-04-12 in Serial-to-Ethernet & ConfigTool. I am connecting the WIZ750SR to a custom board, interfacing with a PIC24 microcontroller in TCP Server mode. When powering on the device, I am able to see it using the Configuration tool, and update its settings. I also have Debug port enabled, and can view the debug output no problem. When I power up the device, it starts in “AT Mode”. I can connect to the configuration server on port 50001, and send a “EX\r\0” command to put it back into “OPEN” mode. However, it will not respond to this command if given by the PIC microcontroller over the serial interface. I have confirmed that the UART settings are correct via oscilloscope (115200, 8 bits, No parity, 1 stop bit, No flow control) for the PIC, and the same settings are applied on the WIZ750SR. When I send the “EX\r\0” command over the Configuration TCP server (50001), I can watch the WIZ750SR change it’s configuration on the Debug port. This is also confirmed with a scan in the Configuration Tool. However, shortly after putting the device into “OPEN” mode I notice some peculiar output on the Debug port: ``` phy id detect error!! phy id detect error!! ================================================== WIZ750SR-1xx >> WIZnet Serial to Ethernet Device >> Firmware version: 1.3.3 Stable ================================================== - Device name: WIZ750SR-1xx - Device mode: TCP_SERVER_MODE + UART IF: [RS-232/TTL] + 115200-8-N-1 / Flow control: NONE - Debug UART port: [UART2] + 115200-8-N-1 / NONE (fixed) - Serial data packing options: - Time: Disabled - Size: Disabled - Char: Disabled - Serial command mode switch code: - Enabled - [2B][2B][2B] (Hex only) - Hardware information: Status pins - Status 1: [PA_10] - PHY link - Status 2: [PA_01] - TCP connection - Hardware information: User I/O pins - UserIO A: [PC_13] - Digital / Input - UserIO B: [PC_12] - Digital / Input - UserIO C: [PC_09] - Digital / Input - UserIO D: [PC_08] - Digital / Input ================================================== # MAC: 00:08:DC:76:DF:96 # IP : 192.168.0.69 / Port: 5000 # GW : 192.168.0.1 # SN : 255.255.255.0 # DNS: 8.8.8.8 > SEG:AT Mode > SEGCP:UDP:STARTED ``` This output will also occur randomly during power on, without changing any settings. I have a few questions: 1. What could cause this behavior? 2. Why am I not able to communicate with the device over UART, despite the matching serial parameters? 3. What is the “SEGCP:UDP:STARTED” message about? I am confused about the UDP part, since the device should be operating in TCP server mode. Please advise. ## Replies ### Reply 1 by Fife, 2024-04-19 After some tinkering, I found a couple things: 1. I had accidentally made the UART connections the wrong way around (TX/RX), this partially solves my issue, as now I can send data over the UART connection. 2. The module boots up in AT mode when it is powered on while there is a physical connection to the Ethernet port. If I disconnect the Ethernet cable when powering it on, the device goes into TCP Server mode. This behavior is still a mystery to me. Although I have partially solved the issue, I am now running into another issue that has been [posted here before with no resolution](https://forum.wiznet.io/t/topic/9513). When I connect to the TCP server, there is no output from the TCP server when sending data through the UART. Furthermore, after sending a few messages, I get an error output on the debug line: “UART Rx Ring buffer Full”. Similarly to the other post, I cannot see any of the data on the debug line, despite the “Serial Debug”->Enable with data being selected. How can I resolve this issue? ### Reply 2 by draoude, 2025-01-24 (in reply to reply 1) Hello, I have a similar error as Fife. When the Ethernet cable is plugged, my WIZ750SR goes strait into AT mode. ```plaintext phy id detect error!! phy id detect error!! phy id detect error!! phy id detect error!! ================================================== WIZ750SR-1xx >> WIZnet Serial to Ethernet Device >> Firmware version: 1.3.3 Stable ================================================== - Device name: WIZ750SR-1xx - Device mode: TCP_SERVER_MODE - Network settings: - Obtaining IP settings: [Static] - TCP/UDP ports + S2E data port: [5000] + TCP/UDP setting port: [50001] + Firmware update port: [50002] - TCP Retransmission retry: [8] - Search ID code: - Disabled: [None] - Ethernet connection password: - Disabled (TCP server / mixed mode only) - Connection timer settings: - Inactivity timer: Disabled - Reconnect interval: [3000] (msec) - Serial settings: - Data UART port: [UART0] + UART IF: [RS-232/TTL] + 115200-8-N-1 / Flow control: NONE - Debug UART port: [UART2] + 115200-8-N-1 / NONE (fixed) - Serial data packing options: - Time: Disabled - Size: Disabled - Char: Disabled - Serial command mode switch code: - Enabled - [2B][2B][2B] (Hex only) - Hardware information: Status pins - Status 1: [PA_10] - PHY link - Status 2: [PA_01] - TCP connection - Hardware information: User I/O pins - UserIO A: [PC_13] - Digital / Input - UserIO B: [PC_12] - Digital / Input - UserIO C: [PC_09] - Digital / Input - UserIO D: [PC_08] - Digital / Input ================================================== # MAC: 00:08:DC:xx:xx:xx # IP : 192.168.11.2 / Port: 5000 # GW : 192.168.11.1 # SN : 255.255.255.0 # DNS: 8.8.8.8 > SEG:AT Mode > SEGCP:UDP:STARTED ``` I can exit this mode with "EX\r\n" but I run into another issue. The link is only one way, I can send data over TCP and get it on the serial port but not the other way around. The only bytes that the device seems react to in "GW Mode" are the "+++" which activates the AT mode. Also there is light on LED D1 but not on D2, D3, D4 or D5 I also got this strange message "phy id detect error!!" Did I do something wrong ? ### Reply 3 by Alan, 2025-01-24 (in reply to reply 1) Is the module you are using WIZ750SR-110 or WIZ750SR? When you power it on and connect the Ethernet cable, does it immediately connect in AT-Mode? If so, what kind of board is connected to the WIZ750SR? ### Reply 4 by draoude, 2025-01-24 (in reply to reply 1) Hello Alan, I'm using the WIZ750SR-TTL Ver1.2. Right now I'm using two FTDI 3V3, one on the "debug" uart and one on the "data" uart. On the Ethernet side, is plug cable is plugged into an USB Ethernet adapter on my computer. Ethernet plugged before boot: > SEG:AT Mode > SEGCP:UDP:STARTED Ethernet plugged after boot: > SEGCP:UDP:STARTED > SEG:TCP_SERVER_MODE:SOCKOPEN" Ethernet plugged during boot: > SEG:AT Mode > SEGCP:UDP:STARTED" The "phy id detect error!!" is happening in all cases. ### Reply 5 by draoude, 2025-01-24 (in reply to reply 1) Hello Alan, I just realized that the whole time I've been flashing the wrong firmware ("WIZ750SR**-1XX**v142_incl_boot.bin" instead of "WIZ750SRv142_incl_boot.bin" ) . Next time I'll be more careful reading the firmware names ! It's working fine now. Thank you for your time ! --- Source: https://maker.wiznet.io/forum/15195