Y201C Technical Manual

Y201C Specification

Y201C has one CAN channel and one ordered serial interface. Ethernet and additional CAN channels are not part of this model.

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Contents

1. Overview
2. Default Settings
3. Wiring and Commissioning
4. Serial Modes and Packetization
5. CAN Configuration and Data Formats
6. Modbus RTU Conversion
7. AT Command Conventions
8. Common AT Commands
9. Configuration Examples
10. Maintenance and Troubleshooting

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1. Overview

Y201C transfers data bidirectionally between one CAN 2.0 A/B channel and one ordered serial interface. The serial interface is available as RS232, RS485, or TTL, depending on the hardware variant. The TTL voltage level is not specified; verify it for the ordered variant before wiring. Configure the gateway through a configuration tool or serial AT commands.

Item	Description
CAN Interface	One CAN channel, 10 to 1000 kbps
Serial Interface	RS232 / RS485 / TTL, depending on the ordered variant
Transfer Modes	DATA, ID_DATA, FRAME, MODBUS
Configuration	Configuration tool or serial AT commands
Maintenance	Backup parameters, factory reset, loopback, heartbeat, filters, serial upgrade

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2. Default Settings

Parameter	Default
Serial Mode	Transparent mode
Serial Format	115200 bps, 8 data bits, 1 stop bit, NONE parity
Serial Flow Control	NFC
Serial Packet Interval	5 ms
Serial Packet Length	Firmware-dependent; query AT+UARTTL1=? or the configuration tool
CAN Baud Rate	100 kbps
CAN Transfer Target	OFF in the AT-command table; set to UART for CAN-to-serial operation
CAN Transfer Mode	DATA
CAN Output Frame	Standard data frame; configure the CAN ID for the application
CAN Loopback	OFF
CAN Packet Split	ON
Serial Heartbeat	OFF; interval 60 s when enabled
CAN Heartbeat	OFF; interval 60000 ms when enabled
CAN Filters	OFF
Command Echo	OFF
Boot Information	Start

Serial baud-rate and packet-length ranges depend on the firmware. Query the target firmware or configuration tool before using 1200 bps, 1024-byte packetization, or 1460-byte packetization.

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3. Wiring and Commissioning

3.1 Hardware Connection

1. Select the serial wiring for the ordered variant.
2. Connect 5 to 36 VDC to + and -, observing polarity.
3. Connect the CAN bus to H, G, and L. H is CAN positive, L is CAN negative, and G is CAN signal ground.
4. Connect the serial side:
   • RS485: A to A, B to B, and signal ground where required.
   • RS232 or TTL: peer TX to device RX, peer RX to device TX, and GND to GND. Verify the TTL voltage level before wiring.
5. Enable the built-in 120 Ω termination only when the gateway is at a bus termination point.
6. Power on the device. POWER should remain on and WORK should blink once per second.

Reload behavior is firmware-dependent. Check its function before using it for a factory reset. AT+RSTCFG restores backup parameters; AT+CLRCFG performs a full factory reset.

3.2 Configuration Tool

1. Connect a PC to the ordered serial interface through the appropriate USB-to-RS485, USB-to-RS232, or TTL adapter.
2. Open the configuration tool and select the CAN device type.
3. Open the serial port with the default parameters 115200/N/8/1 and NFC flow control.
4. Set the CAN baud rate, transfer target, transfer mode, frame parameters, packet split, heartbeat, and filters as required.
5. Save the parameters and reboot the device.
6. Send test data from both sides and verify the UART and CAN1 indicators.

3.3 AT Configuration Entry

AT commands are available through the serial port. Use this sequence from transparent mode:

1. Send +++.
2. Wait longer than the packet interval and less than 3 s; 500 ms is recommended.
3. Send a.
4. Wait for +ok before sending AT commands.

The device pauses CAN transparent output for up to about 3 s after receiving +++, but other data can still interfere with the sequence. AT mode is not retained after power loss or reboot.

To return to transparent mode, send AT+EXIT\r\n and wait for OK, or reboot the device.

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4. Serial Modes and Packetization

4.1 Serial Working Modes

• Transparent mode, default: Serial data is packetized and forwarded through the CAN channel.
• AT command mode: Serial input is interpreted as AT commands. CAN transparent data is discarded while the device processes commands.

Each command line accepts one AT command. New settings are saved to the runtime parameter area and take effect after reboot.

4.2 Packetization

The gateway forwards serial data when either condition is met:

• Length trigger: received data reaches the configured packet length.
• Interval trigger: the gap between adjacent characters reaches the configured packet interval.

The active packet-length range and default depend on the firmware. Use the value reported by the target firmware's help response or configuration tool.

Example:

AT+UARTTL1=5,1460

4.3 Serial Heartbeat

The serial heartbeat sends a user-defined hexadecimal packet at a configured interval.

Parameter	Range / Default
Enable	OFF / ON, default OFF
Interval	1 to 86400 s, default 60 s
Data	Hexadecimal string, 2 to 64 bytes

Use AT+HEARTEN1, AT+HEARTTM1, and AT+HEARTDAT1 to configure it.

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5. CAN Configuration and Data Formats

5.1 CAN Baud Rate

The CAN channel supports 10 to 1000 kbps and defaults to 100 kbps. The supported rate list may differ by firmware; query the target firmware before using 800 kbps.

The AT command expresses the rate in kbps. For example, 100 kbps is written as 100 and 1 Mbps as 1000.

5.2 Transfer Target

Y201C has one CAN channel and one serial channel. Set the CAN transfer target to UART for bidirectional CAN-to-serial transfer:

AT+CAN1=100,UART,DATA

Use UART as the transfer target on Y201C. CAN and ALL are transfer targets for multi-CAN variants.

5.3 Transfer Modes

Mode	Serial-to-CAN Behavior	CAN-to-Serial Behavior
DATA	Places the serial packet in the CAN data field and uses the configured CAN frame parameters	Returns the CAN data field only
ID_DATA	Parses the serial packet as CAN ID followed by data; standard-frame ID uses 2 bytes and extended-frame ID uses 4 bytes	Returns CAN ID followed by data
FRAME	Parses a complete frame containing frame information, a 4-byte ID, and 0 to 8 data bytes	Returns the same complete-frame structure
MODBUS	Converts validated Modbus RTU data to segmented CAN data	Reassembles segmented CAN data and adds the Modbus RTU CRC before serial output

Select a mode with the third parameter of AT+CAN1:

AT+CAN1=100,UART,DATA
AT+CAN1=100,UART,ID_DATA
AT+CAN1=100,UART,FRAME
AT+CAN1=100,UART,MODBUS

5.4 Output Frame Parameters

For DATA mode, configure the CAN frame format, frame type, and ID separately:

AT+CAN1FRAME=STD,DATA,128

Parameter	Values
Frame Format	STD standard frame / EXT extended frame
Frame Type	DATA data frame / REMOTE remote frame
Frame ID	Decimal CAN ID; use the range supported by the selected frame format

These parameters define the CAN frame generated from serial data. They do not rewrite or filter frame information received directly from the CAN bus.

5.5 Complete-Frame Format

FRAME mode uses this serial structure:

[Frame Information: 1 byte][CAN ID: 4 bytes][Data: 0 to 8 bytes]

The frame-information byte uses these bits:

Bits	Field	Meaning
7	IDE	0 standard frame; 1 extended frame
6	RTR	0 data frame; 1 remote frame
5 to 4	Reserved	Reserved
3 to 0	DLC	CAN data length

The CAN ID field occupies 4 bytes for both standard and extended frames. For example, a standard data frame with ID 0x123 and eight data bytes is represented as:

08 00 00 01 23 11 22 33 44 55 66 77 88

5.6 Packet Splitting

When packet splitting is enabled, serial data that exceeds the maximum CAN data length is divided into multiple CAN frames. When packet splitting is disabled, an overlength serial packet is treated as invalid and is not forwarded.

AT+CAN1SPLIT=ON

For DATA mode, each CAN frame carries up to eight data bytes. In FRAME mode, each complete frame is checked for a valid frame-information byte, CAN ID, and data length before forwarding.

5.7 CAN Loopback

Loopback causes CAN frames transmitted by the channel to be received by the same channel and processed according to the configured transfer direction and mode. Use it for bench testing only.

AT+CAN1LOOP=ON

Disable loopback before connecting the gateway to a live CAN bus. CAN filters still apply to loopback data.

5.8 CAN Heartbeat

The CAN heartbeat periodically transmits a configured CAN frame.

AT+CAN1HTEN=ON
AT+CAN1HTTM=60000
AT+CAN1HTFRAME=STD,DATA,1792
AT+CAN1HTDATA=1122334455667788

Parameter	Range / Default
Enable	OFF / ON, default OFF
Interval	10 to 86400000 ms, default 60000 ms
Frame Format	STD / EXT, default STD
Frame Type	DATA / REMOTE, default DATA
Frame ID	Decimal, default 1792 (0x700)
Data	Hexadecimal string, 2 to 16 bytes

5.9 CAN Filters

Y201C provides eight independent filters for the CAN channel. A frame is accepted when it matches any enabled filter.

Filter Parameter	Values
Status	ON / OFF, default OFF
Frame Format	STD / EXT / ALL
Filter Mode	ID exact ID / MASK ID-plus-mask
ID	Decimal, 0 to 536870911
Mask	Decimal; default 536870911 (0x1FFFFFFF)

For filter m, use AT+CAN1FLTm, replacing m with 1 to 8. With MASK mode, all ID bits whose mask bit is 1 must match the configured ID.

Example for filter 2:

AT+CAN1FLT2=ON,STD,MASK,291,256

This accepts standard frames whose masked ID matches decimal 291 (0x123) with mask decimal 256 (0x100).

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6. Modbus RTU Conversion

6.1 Function Description

In MODBUS mode, the serial side uses standard Modbus RTU. The gateway validates the serial frame and discards invalid data. It does not operate as a Modbus master or slave; it verifies and forwards protocol data.

The maximum Modbus RTU frame length is 219 bytes. When CAN data is reassembled for serial output, the gateway completes the Modbus RTU CRC before forwarding the frame.

Modbus conversion does not support CAN-to-CAN forwarding.

6.2 CAN Segmentation

CAN data uses one segmentation header byte followed by up to seven Modbus data bytes per CAN frame:

CAN data 1: [Segment Marker][Segment Type][Segment Counter]
CAN data 2 to 8: Modbus data bytes

The segmentation header uses:

Bits	Field	Meaning
7	Segment marker	0 standalone frame; 1 segmented frame
6 to 5	Segment type	0 first; 1 middle; 2 last
4 to 0	Segment counter	Segment sequence number, 1 to 31

Configure Modbus conversion with:

AT+CAN1=100,UART,MODBUS

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7. AT Command Conventions

7.1 Format Rules

• Commands start with AT+ and end with \r\n.
• Commands are case-insensitive; uppercase is recommended.
• One command is allowed per line.
• The maximum command length is 256 bytes.
• Separate multiple parameters with an ASCII comma.
• Wait for the previous response before sending the next command; the maximum command timeout is about 5 s.

7.2 Call Types

Type	Send Format	Return Format
Query	AT+CMD\r\n or AT+CMD?\r\n	+CMD:value followed by OK
Set	AT+CMD=value1,value2...\r\n	OK
Help	AT+CMD=?\r\n	+CMD:(range...) followed by OK

Command examples omit the final \r\n unless noted otherwise.

7.3 Error Codes

Error Code	Meaning
ARGS	Invalid parameter length, value, format, or range
ARGC	Invalid number of parameters
CMD_UNKNOWN	Unknown command
CMD_FORMAT	Invalid command format, such as missing AT+
CMD_LENGTH	Command exceeds the maximum length
DEV_MEMORY	Device memory error
DEV_SAVE	Parameter save error

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8. Common AT Commands

8.1 Device and Parameter Control

Command	Function	Notes
AT+LIST	List supported commands	Query the command set on the target firmware
AT+VER	Query firmware version	Returns the version string
AT+DEVINFO	Query device information	Model, version, MAC, build, production time, and serial number
AT+ECHO	Query or set command echo	ON / OFF; default OFF
AT+BOOTINFO	Query or set boot information	1 to 16 bytes; default Start
AT+REBOOT	Reboot the device	Applies saved runtime parameters after reboot
AT+EXIT	Exit AT mode	Returns to transparent mode
AT+RSTCFG	Restore backup parameters and reboot	Equivalent to Reload recovery
AT+BKCFG	Back up current runtime parameters	Recommended after commissioning
AT+CLRCFG	Restore factory parameters and reboot	Full factory reset

8.2 Serial Parameters

Command	Function	Range / Default
AT+UART1=<baud>,<data>,<stop>,<parity>,<fc>	Serial settings	Baud list is firmware-dependent; default 115200,8,1,NONE,NFC
AT+UARTTL1=<tm>,<len>	Packet interval and length	tm 1 to 300 ms, default 5; len follows the firmware's reported range
AT+HEARTEN1=<state>	Serial heartbeat enable	ON / OFF; default OFF
AT+HEARTTM1=<time>	Serial heartbeat interval	1 to 86400 s, default 60
AT+HEARTDAT1=<data>	Serial heartbeat data	Hexadecimal string, 2 to 64 bytes

8.3 CAN Parameters

Command	Function	Range / Default
AT+CAN1=<bps>,<target>,<mode>	CAN rate, transfer target, and mode	target=UART; mode DATA / ID_DATA / FRAME / MODBUS; rate default 100
AT+CAN1FRAME=<format>,<type>,<id>	Output frame parameters	STD/EXT, DATA/REMOTE, decimal ID
AT+CAN1LOOP=<state>	CAN loopback	ON / OFF; default OFF
AT+CAN1SPLIT=<state>	Serial data splitting	ON / OFF; default ON
AT+CAN1HTEN=<state>	CAN heartbeat enable	ON / OFF; default OFF
AT+CAN1HTTM=<time>	CAN heartbeat interval	10 to 86400000 ms, default 60000
AT+CAN1HTFRAME=<format>,<type>,<id>	CAN heartbeat frame	Default STD,DATA,1792
AT+CAN1HTDATA=<data>	CAN heartbeat data	Hexadecimal string, 2 to 16 bytes
AT+CAN1FLTm=<state>,<format>,<mode>,<id>,<mask>	Filter m	m=1 to 8; STD/EXT/ALL; ID/MASK

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9. Configuration Examples

9.1 CAN-to-Serial Data-Only Transfer

1. Enter AT mode with +++, a short delay, and a; wait for +ok.
2. Match the serial parameters to the host:

AT+UART1=115200,8,1,NONE,NFC
AT+UARTTL1=5,1460

3. Configure the CAN channel and output frame:

AT+CAN1=100,UART,DATA
AT+CAN1FRAME=STD,DATA,128
AT+CAN1SPLIT=ON

4. Save a recovery copy and reboot:

AT+BKCFG
AT+REBOOT

5. Send up to eight data bytes from the serial side and check that the CAN analyzer receives a standard data frame with ID 128.

9.2 Complete-Frame Transfer

Use complete-frame mode when the host must specify or receive the CAN frame format, frame type, ID, and data length:

AT+CAN1=100,UART,FRAME
AT+BKCFG
AT+REBOOT

Send and receive the complete-frame structure described in 5.5.

9.3 Modbus RTU over CAN

1. Match the serial parameters to the Modbus RTU master or slave.
2. Select Modbus conversion:

AT+CAN1=100,UART,MODBUS
AT+BKCFG
AT+REBOOT

3. Send a valid Modbus RTU frame from the serial side.
4. Reassemble the segmented CAN frames at the remote CAN endpoint according to 6.2.
5. Check that invalid CRC or malformed Modbus frames are discarded.

9.4 Filtering and Heartbeat

Enable only the filters and heartbeat packets required by the application:

AT+CAN1FLT1=ON,STD,MASK,291,536870911
AT+CAN1HTEN=ON
AT+CAN1HTTM=60000
AT+CAN1HTFRAME=STD,DATA,1792
AT+CAN1HTDATA=1122334455667788
AT+BKCFG
AT+REBOOT

Review the CAN analyzer after reboot to see whether unrelated IDs are filtered and the heartbeat is transmitted at the expected interval.

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10. Maintenance and Troubleshooting

10.1 Parameter Areas

The gateway uses three parameter areas:

• Runtime area: The active configuration queried and changed by AT commands.
• Backup area: A recovery copy written by AT+BKCFG and restored by AT+RSTCFG or Reload.
• Factory area: Manufacturer-fixed defaults restored by AT+CLRCFG.

Recommended workflow:

1. Configure and test the runtime parameters.
2. Run AT+BKCFG after commissioning.
3. Use AT+RSTCFG when the backup configuration must be restored.
4. Use AT+CLRCFG only when a full factory reset is required.

10.2 Firmware Upgrade

1. Power off the gateway.
2. Hold the Reload button while powering it on.
3. Release the button after the device enters serial upgrade mode; WORK fast-blinks.
4. Use the configuration tool to load the firmware.
5. Recheck the serial, CAN, heartbeat, filter, and packetization settings after the upgrade.

10.3 Troubleshooting

Symptom	Possible Cause	Recommended Action
No POWER LED	Power wiring or polarity is wrong	Check +/-, supply voltage, terminal seating, and reverse polarity
No +ok after AT entry	Timing is incorrect or another data source interferes	Retry +++, wait about 500 ms, send a, and wait for +ok
Serial data does not reach CAN	Transfer target is OFF, wrong CAN rate, or wrong mode	Set AT+CAN1=...,UART,...; match the CAN baud rate and frame mode
CAN data does not reach serial	Wrong wiring, filter, or CAN frame format	Check H/G/L, disable filters for testing, and verify DATA, ID_DATA, or FRAME format
CAN bus reports errors	Rate mismatch, wiring fault, or termination problem	Match the baud rate, check polarity and signal ground, and apply 120 Ω termination only at the bus end
Long serial packet is discarded	Packet splitting is disabled or packet length exceeds the active limit	Enable AT+CAN1SPLIT=ON and query AT+UARTTL1=?
Modbus frame is discarded	CRC, function frame, or segment data is invalid	Validate the Modbus RTU frame and reassemble CAN segments in order
Heartbeat is absent	Heartbeat is disabled or parameters were not applied	Enable the correct heartbeat, save with AT+BKCFG, and reboot
Filtered data is missing	An enabled filter does not match the CAN ID	Disable filters temporarily or check STD/EXT, ID, and mask values
Parameters return after Reload	Desired values were not backed up	Reconfigure the device and run AT+BKCFG

10.4 LED Reference

• POWER steady on: power is present.
• WORK blinks once per second: normal operation.
• WORK fast-blinks: serial firmware upgrade mode.
• UART TX / UART RX: serial activity.
• CAN1: CAN data activity.
• CAN1 ERR: CAN error indication.

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• Manufacturer: Hunan YenGear Tech Co., Ltd.
• Address: Room 21014, Building 1, Fudi Xingguang Tiandi, Yingxin Road, Yuhua District, Changsha, Hunan, China
• Email: [email protected]
• Website: www.yengear.com