ROHM ML62Q203x LogiCoA RMOS Microcontroller for Power Supply Control

Specifications

• Product Name: LogiCoATM Power Solutions
• Manufacturer: ROHM Co., Ltd.
• Communication Protocol: UART
• Operating System Compatibility: Windows 10 64-bit
• Required Software: Microsoft Excel 64-bit version
• Power Supply Output: 12V, 1A or higher

Introduction

The microcontroller for Power Supply Control ML62Q203x/ML62Q204x (hereinafter referred to as ML62Q20xx group) has two communication interfaces of UART/I2C. RMOS (Real-time Micro Operating System) provided by us uses UART to create a frame configuration and a packet configuration in advance and provide it as a software that enables communication control using Excel VBA. Communications between the MCU and PC can be easily performed by writing RMOS and setting commands arbitrarily in Excel VBA. The user can also easily create a GUI to control communications. Another benefit is that it implements a communications protocol that can communicate with up to 32 power supplies for a single PC by software processing RMOS. This application note introduces the protocol for serial communication using UART, explanations of communication functions (such as how to append to commands), and shows how to use the communication GUI development environment. The communication described here uses a buck DCDC converter (hereafter buck converter) EVK, LogiCoA001-EVK-001 (hereafter buck converter EVK).

Usage environment

Software and Equipment
Communication using RMOS described in this manual is performed using the following.

1. Buck converter EVK
2. USB-UART convert module: FT234x FTDI (mounted on 1)
3. Windows PC(Windows10 64bit)
4. On-chip emulator “EASE1000 V2”
5. RMOS project file(file to be read into LEXIDE-Ω and used)
6. Microsoft Excel 64-bit version (Operation check: Microsoft 365 MSO, Office 365 MSO)
7. Excel file “RMOS_CommunicationControl_LogiCoA001-EVK-001.xls”
8. Regulated DC power supply (Performance: Output-voltage 12V, Output current 1A or higher)
9. Digital multimeter

Figure 1-1 shows a simplified diagram for communication. When checking the operation, disconnect the on-chip emulator and connect the measuring device to the I/O pin of the buck converter EVK.

For details on how to connect the Figure 1-1 buck converter EVK and on-chip emulator, and how to write RMOS codes, refer to RMOS application note [1].

Files in RMOS folders are required for communication control
Table 1-1 describes the RMOS file necessary for communication control described in this manual. How to change the file name of the table and how to check the operation after changing the description are explained in the later chapters.

Table 1-1. Files in RMOS folders are required for communication control

No.	Folder name	File name	Description	Changeable part
1	00_System	00S93_Func_Select.s	Function setting of OS during program debugging	Communication mode
2	10_Setting	10S01_Parameter_Init.s	Set the initial value of power supply operation parameters	Communication address
3	“	※10S70_UART_Set.s	UART assignment and operation setting	※No need to change
4	30_Info_module	30I01_InfoCMD_Exec.asm	Write the program of communication command	Add program of additional command
5	“	30I11_InfoCMD_Table_def.s	Communication command assignment	Assign labels for additional commands
6	90_Header	※93H010_InfoTxRx_Header.s	Describes a program for processing transmission and reception data	※No need to change

Communication protocol

This chapter describes the configuration of serial communication using UART set in RMOS. The hardware used to communicate between the microcontroller and PC is UART., RMOS has a communication protocol that consists of 6 frames per packet by software processing. This packet configuration enables one PC to perform communication control of 32 power supplies and communication from PC to the power supply circuitry using several commands. Table 2-1 indicates UART hardware configuration and Table 2-2 indicates RMOS communication frame configuration. All the initialization settings in the table are set in the “10S70_UART_Set.s.s” file. 2nd bit of Table 2-2 is identified by the frame identification bit, the first frame (Frm0) is identified by “1”, and the remaining frames (Frm1-Frm5) are identified by “0”.

Table 2-1. UART hardware configuration 

	Setting
Baud rate	9600bps
Data length	8bit
communication direction	LSB first
Parity	Use, Even
Stop bit	1bit

Table 2-2. Frame configuration 

bit	Assignment
1	Start
2	Data (Identification)
3	Data
4	Data
5	Data
6	Data
7	Data
8	Data
9	Data
10	Parity
11	Stop

Figure 2-1 packet configuration is described below. One packet of transmission/reception consists of 6 frames (= total 42 bits in length): address length (5 bits) + decision bit (1 bit) + data length (32 bits) + checksum length (4 bits). All the software processes that process 6 frames into one packet are described in the “93H010_InfoTxRx_Header.s.s” file. There are two transmission methods: TX32 and TX16 (the communication explained in this document is set by TX16). TX32 can transmit the data of 32-bit length up to 7th-38th bit of the packet to the microcontroller, but the number of commands is limited to one. On the other hand, TX16 has 8bit lengths for command groups (CmdGr) and command numbers (CmdNo) from the 7th to 22nd bit, and up to 65536 types of commands can be used in combination (For the communication commands of the buck converter, areas from 0-15 for CmdGr and from 0-31 for CmdNo can be used.). The data to be transmitted to the microcontroller is 16 bits in length from the 23rd to the 38th bit. ADR (1st-5th bit) of Frm0 is assigned to the connected devices, and up to 32 power supplies can be connected simultaneously. 6bit of Frm0 is determined by TX32 and TX16, where “1” is TX32 and “0” is TX16. The chksum(39th-42nd bit) is an error detection and judgment bit. This bit is used to detect and judge errors in the communication data of all 6 frames. In addition, the receiver RX returns the data of 32 bits in response to the transmitted command.

Communication method

Initialization Settings of Excel VBA and RMOS

Excel VBA setting
This section describes the initialization of Excel files required for communication between the PC and the microcontroller. First, start the “RMOS_CommunicationControl_LogiCoA001-EVK-001.xls” file downloaded from ROHM website. The operating sheets are described in later chapters.

Next, check whether Excel is set up to use VBA macros. If “Development” tab is displayed in Excel (Figure 3-2), VBA macro can be executed.

If “Developer” tab is not displayed, follow the step below to configure the settings.

1. Click “File” tab > “Options” > “Customize Ribbon”.
2. Check the “Developer” box in the “Customize the Ribbon” list.
3. Click “OK”.
4. Check the window that the “Developer” tab is displayed.

Also, the first time the user opens an Excel file, “Macro have been disabled” message is displayed. Click on “Enable Content” button to improve. Once the user does this in the first use, the user will not receive the warning message the next time the user launches Excel file.

Setting of the communication address and communication mode
Check the serial communication mode of the UART and the microcontroller address setting. Configure the settings so that Excel filename matches RMOS description as shown in Figure 3-3.

• Blue: The value in D3 cell is the address of the microcontroller. In the provided RMOS, PS_ADR_init “31” in “10S01_Parameter_Init_Init_ Init.s” file is the address of the microcontroller. There is no need to change the address in this manual. However, when connecting more than one power supply to PC for communication control, set the address of each power supply on RMOS and specify the address of the target power supply in Excel.
• Yellow: N3 cell is used to change UART communication mode. The communication in LogiCoATM power solution has two connection methods: two wires and one wire. “InfoTxRx_mode” on line 9 of “00S93_Func_Select.s” file can be set to “0” for two wires and “1” for one wire connection mode. The buck converter EVK described in this manual is designed for one wire communication.

Checking and setting COM port number
Please acquire COM port number of TxRxInterface sheet. COM port is a type of communication port for connecting PC to an external device and is used for serial communication. When USB cable is connected to the USB-UART convert module, Figure 3-4 will show “USB Serial Port (COM6)” in Windows Device Manager (Driver will install automatically if connected to a network). The number “COM*” is COM port number. The number varies depending on PC and the USB-UART convert module.

NOTE: Even if the USB cable is connected, the driver may not be automatically installed and the Figure 3-4 window may not display. In this case, the driver must be downloaded and installed from the FTDI website. This COM number must be specified when communicating with Excel file. In the TxRxInterface sheet, VBA macro automatically acquires the COM port number of USB module. When click “Port Read” on Figure 3-5, the number is displayed in H3 cell.

If communication between the PC and the MCU fails, first check that the COM port number has been acquired correctly. If more than one USB is connected, the port number may not be acquired from the Excel file. To resolve this, click “Port Read” again, or check COM number in Device Manager and input the COM number in the H3 cell.

How to use the TxRxInterface Sheet
Perform produces 1 to 4 below to perform communication using the TxRxInterface sheet.

1. Input CmdGr (command group) in decimal.
2. Input CmdNo (command number) in decimal.
3. Input DATA in decimal. Figure 3-6 is inputting commands to change the D/A converter code in the microcontroller. By inputting CmdGr=”4″ and CmdNo= “0”, the code value of the microcomputer D/A converters can be changed to the value inputted in DATA. Depending on the command, certain register values in the microcontroller can be received. See Section 4 “Communication Commands List” for the commands that can be communicated with the buck converter EVK.
4. Click, “Send16”. When the button is clicked, data is transmitted to the microcontroller, and the value is displayed in the cell of the receiving item below the 19th line when communication is successfully performed. In Figure 3-6, since the setting value is “101”, “101” is displayed in J23 cell.

M26 cell displays 6 frames of received data and error messages. An error message is displayed when USB cable is not connected to the USB-UART convert module, when a communication error occurs, or when there is no description of the communication command in RMOS. The description of VBA macro registered in this sheet does not need to be changed because various GUI are created based on VBA macro in TxRxInterface sheet.

How to use TinyGUI Sheet
This section explains how to use the TinyGUI sheet. This sheet simplifies manual operation on the TxRxInterface sheet so that communication can be performed only by button operation using a VBA macro. Provided Excel file incorporates VBA macros to change the output voltage of the buck converter EVK in the TinyGUI sheet. Figure 3-7 shows the macro button on the TinyGUI sheet. VBA macro is registered in buttons 1 to 4. Figure 3-8 shows the description of VBA macros registered in buttons 1 to 4. This chapter describes an experimental system in which 12V is applied to the input voltage of the buck converter EVK as an example.

1. Set_Vo button: Transmits the value of F32 cell to the microcontroller.
2. Down button: Subtracts the code of D/A converter for each number written in H32 cell and transmits the value to the microcontroller.
3. Up button: Adds the code of D/A converter for each number written in H32 cell and transmits the value to the microcontroller.
4. Read_Vo button: The D/A converter code is received from the microcontroller and the received value is displayed in O32 cell.

The output-voltage Vo of the buck converter EVK is determined by the code of D/A converter, and the following equation is established.

• …VDD(microcontroller supply voltage)=5V, R29=51Ω, R30=3.3kΩ, R31=2.2kΩ

The output voltage Vo of the buck converter EVK can be changed using the setting code calculated from the above equation (Ex. 3.3V=”67, 5V=”101 and 9V=”181). In actual operation, after inputting the value of F32 cell, click button and check that the output voltage of buck converter EVK has changed.

Commands implemented in RMOS
This section describes the program of the communication commands already implemented in RMOS (version “RMOSVer=1.00, OSBuildNo=007, PSFMNo=001, PSFMVer=1.00, PSFMBuildNo=004”). The following two types of commands are described in Section 4 “Communication Commands”: Read system commands (commands to read microcontroller values) and Set system commands (commands to write to the MCU). Table 3-1 summarizes the files in “30 Info_module” folder described in this chapter. Figure 3-9 shows the window in “30 Info_module” folder of LEXIDE-Ω.

Table 3-1. Files in the “30_Info_module” folder

No.	File name	Description	Changes
1	30I01_InfoCMD_Exec.asm	Write the program of communication command.	Add a program of additional commands
2	30I11_InfoCMD_Table_def.s	Communication command assignment	Assign labels for additional commands

1. TX16 of received data from PC is processed in “93H010_InfoTxRx_Header.s” file. And CmdGr and CmdNo are calculated.
2. Calculated command value indicates the address value of the communication command table in “30I11_InfoCMD_Table_ def.s” file.
3. Jump to the label in “30I01_InfoCMD_Exec.asm” file that matches the read label name in 2 and executes the corresponding program. Note that “93H010_InfoTxRx_Header.s” file has a description that processes the transmitted and received data. Normally, it does not need to be edited. Read and Set commands described in “30I11_InfoCMD_Table_def.s” file and “30I01_InfoCMD_Exec.asm” file are described in (1), (2) below.

Read Command
Figure 3-10 shows the descriptions and operations of Read command. The following programs describe how to read an input voltage AD value or 2 times moving average value (when CmdGr = “0” and CmdNo = “0”).

1. The beginning label name of the description to acquire the input voltage AD value is assigned in “30I11_InfoCMD_Table_ def.s” file. The received data is processed in “93H010_InfoTxRx_Header.s” file and jumped to “InfoCMD_Read_DDVin” label when CmdGr = “0” and CmdNo = “0”.
2. The label name assigned in 1 is described, and the description below the label is executed.
3. Compare data received from the PC and jump target descriptions accordingly.
   • If CmdGr = “0”, CmdNo = “0”, DATA = “0”, go to 4
   • If CmdGr = “0”, CmdNo = “0”, DATA = “1”, go to 6
4. The label jumped from the processing of 3 is described. Then, the label name is “Read_DDVin_AD”.
5. Acquire “DDVin_ADvalue”(input voltage AD value) and jump to the communication process to transmit the return value to PC.
6. The label jumped from the processing of 3 is described. Then, the label name is “Read_DDVin_2MA”.
7. Acquire “DDVin_2MAvalue”(input voltage 2 times moving average AD value) and jump to the communication process to transmit the return value to PC.

Set Command
Figure 3-11 shows the descriptions and operations of the Set command. The following commands describe how to acquire and change the output voltage (when CmdGr = “4” and CmdNo = “0”).

1. The beginning label name of the description that acquires or changes the output voltage is assigned in “30I11_InfoCMD_Table _def.s” file. The data is processed in “93H010_InfoTxRx_Header.s” file and jumped to “InfoCMD_Set_DDVo” label when CmdGr = “4” and CmdNo = “0”.
2. The label name assigned in 1 is described, and the description below the label is executed.
3. Compare data received from PC and jump target descriptions accordingly.
   • If CmdGr = “4”, CmdNo = “0”, DATA = “65535”, go to 4
   • If CmdGr = “4”, CmdNo = “0”, DATA = “below 65535”, go to 5
4. Acquire “DDVo_DACset”(output-voltage setting value) and jump to the communication process to transmit the return value to PC. This description is the same as the Read command. When DATA=”65535” is inputted, “DDVo_DACset” is read from the microcontroller.
5. The label jumped from the processing of 3 is described. Then, the label name is “CHG_DDVo”.
6. Change “DDVo_DACset” to the value of DATA and jump to the communication process to transmit the return value to PC. The value of “DDVo_DACset” in the microcontroller can be changed by this description.

Please use TxRxInterface sheet of Excel file to check the operation of the communication commands (Refer to 3-3 “How to use TinyGUI sheet”). Even if DATA=”65535″ is transmitted immediately after Excel is started, the initialization setting is “101”, so the reception status remains unchanged.

How to Add Set Command
In the Set commands in Chapter 4 “Communication Commands List”, some of the commands are not described except for CmdGr=”4″ and CmdNo=”0″. Therefore, it is necessary to add them. Figure 3-12 shows an example of adding a communication command to change the startup voltage setting value in steps 1 to 3. To use a command other than this one, write the corresponding state variable name from Table 4-1 in the red box.

1. The program to set the starting voltage value “DDVin_RISEset” is written in CmdGr=”4″ and CmdNo=”8″.
2. Acquire “DDVin_RISEset”(startup voltage setting value) and jump to the communication process to transmit the return value to PC.
3. Change “DDVin_RISEset” to the value of DATA and jump to the communication process to transmit the return value to PC.

How to add command in UserFree area
This section describes how to read and change state variables not listed in Chapter 4, “Communication Commands List”. Follow the steps 1 to 3 below to add more commands. Program area that can be freely described by user are provided in CmdGr=”15″.

1. Assign labels to any CmdNo.
2. Describe the label assigned in 1 at the beginning of the description.
3. Describe the command processing. Refer to Figures 3-10 and 3-11 for how to describe the program.

How to add a GUI
This chapter describes how to operate the TxRxInterface sheet using the GUI. This makes debugging the power supply easier, as power supply parameters can be easily changed and acquired. GUI can create in TinyGUI sheet of Excel file. User can add GUI as shown in steps 1 to 5 below. In this chapter, GUI is created by referring to Chapter 3-5 (1) “How to add Set command” and changing the startup voltage (CmdGr=”4″ and CmdNo=”8″).

1. Copy macro buttons and cells in a sheet. And rename macro buttons.
2. Copy the pre-registered VBA macro (Figures 3-8) to the line below the arrow.
3. VBA macro is rewritten according to the description on RMOS or the cell copied in Step 1.
4. Register the macro name added with VBA to the macro button. (Steps of (1) to (5))
5. Check the operation of the created GUI. (Steps of (1) to (6))

User can easily create a GUI for communication using the above steps. In the GUI shown in step 5, the startup voltage is input as AD value, but it can also be input as a voltage value by the function of Excel file. For the calculation method for converting startup voltage AD value to the voltage value, refer to the User’s Guide [2] and Operating Manual [3] of the buck converter. Parameters such as stop voltage, dead time, and OCP (over current protection) can also be added to the GUI in the same step as the startup voltage.

Communication Commands List

Table 4-1 contains a list of CmdGr and CmdNo functions. In RMOS (version “RMOSVer=1.00, OSBuildNo=007, PSFMNo=001, PSFMVer=1.00, PSFMBuildNo=004”) in this manual, CmdGr of 1 to 15 can be used, and CmdNo of 1 to 31 can be used. Please note that the command’s configuration in the table 4-1 may change due to future RMOS upgrades.

Table 4-1. Communication Commands List

Read commands

CmdGr	CmdNo	DATA	Command label name	State variable name	Command description
0	0	0	InfoCMD_Read_DDVin	DDVin_ADvalue	Input voltage AD value
		1		DDVin_2MAvalue	2 times moving average AD
	1	0	InfoCMD_Read_DDVo	DDVo_ADvalue	Output voltage AD value
		1		DDVo_2MAvalue	2 times moving average AD
	2	0	InfoCMD_Read_DDIdPGA	DDIdPGA_ADvalue	Drain current AD value
		1		DDIdPGA_2MAvalue	2 times moving average AD
		2		DDIdPGA_8MAvalue	8 times moving average AD

Set commands

CmdGr	CmdNo	DATA	Command label name	State variable name	Command description
4	0	Value	InfoCMD_Set_DDVo	DDVo_DACset	Output Voltage setting
	8	Value	InfoCMD_Set_DDVinRISE	DDVin_RISEset	Startup voltage setting
	9	Value	InfoCMD_Set_DDVinFALL	DDVin_FALLset	Stop voltage setting
5	0	Value	InfoCMD_DD0_Fsw	Fsw_CTset	Switching Frequency setting
	16	Value	InfoCMD_DD0_TonMax	dmax_CTset	Switching device maximum duty setting
6	0	Value	InfoCMD_DD0_OCP	DDOCP_Ioset	OCP setting
7	0	Value	InfoCMD_DD0_OVP	DDOVP_VoADset	OVP setting
	16	Value	InfoCMD_DD0_LVP	DDLVP_VoADset	LVP setting
11	0	Value	InfoCMD_DD0_DeadTime0	DTimeHoffLon_CTset	Dead time 0 count value setting
	1	value	InfoCMD_DD0_DeadTime1	DTimeLoffHon_CTset	Dead time 1 count value setting

Please note that CmdGr and CmdNo that are not specified above are reserved areas and may add programs in future RMOS upgrades or EVK releases.

UserFree commands

CmdGr	CmdNo	DATA	Command label name	State variable name	Command’s description
15	0	–	Can be freely described	–	–
	＊	＊	＊	＊	＊
	＊	＊	＊	＊	＊
	31	–	–	–	–

References

1. 66AN147E, Rev.001, Operating system for switching power control MCU “RMOS”
2. 66UG090E, Rev.001, Synchronous Buck DCDC Converter Evaluation Board LogiCoA001-EVK-001
3. 66AN153E, Rev.001, Analog-Digital Hybrid Control Power Supply Synchronous Buck DCDC Converter Operating Instructions

Revision History

Date	Revision Number	Description
5. June. 2024	001	Initial release

Notice 

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FAQs

Q: What is the purpose of the RMOS project file?
A: The RMOS project file is used to read into LEXIDE for programming and communication control.

Q: How many frames are there per packet in the communication protocol?
A: The communication protocol consists of 6 frames per packet.

Documents / Resources

ROHM ML62Q203x LogiCoA RMOS Microcontroller for Power Supply Control [pdf] User Guide ML62Q203x, ML62Q203x LogiCoA RMOS Microcontroller for Power Supply Control, LogiCoA RMOS Microcontroller for Power Supply Control, RMOS Microcontroller for Power Supply Control, Microcontroller for Power Supply Control, Power Supply Control

References

• User Manual