Custom RDM6300 firmware RFID reader/writter for EM4100, T5577 ICs

So I bought an RDM6300 RFID card/tag reader and realized that it cannot write tags. Thus, I have decided to add writing capability and to include support for other RFID chips. Original firmware supports only chips that uses the EM4100 protocol but by replacing it with a custom firmware, new protocols can be added.

RDM6300 v2 uses the C8051F330 microcontroller from Silabs which is quite old and has only ~7.5kB of program memory that limits how much the functionality can be expanded. If there is interest, I might make a custom board with a more modern microcontroller and also include a PCB coil to reduce the cost of the RFID module.

Features

RFID frequency: 125kHz

RFID mode: read/write

Supported ICs:

• EM4100
• T55xx (e.g. T5577, Blue Trinket tags)
  

Bit rates: RF/16, RF/32, RF/64

Supported encoding: Manchester

Supported Sequence Terminators (ST):

• Default (ST bit=0)
• ST bit=1 and X-Mode=0
• ST bit=1 and X-Mode=1: not supported as it didn't provide reliable results
  

 Interface: UART, 115200, 8-bit

 

RDM6300 pinout and schematic 

This, I believe, is the version 2 of the RDM6300 module.

• 5V and GND: DC power supply with at least 50mA current capability. The input is protected from reverse voltage by the diode D1. A 3V3 voltage regulator will use this supply to power the C8051F330 micro-controller which is a 3V3 type.
• 3V3 and GND: the micro-controller can be powered directly using a 3.3V source but I think this is mostly for factory programming. Can be left unconnected.
  
• C2CK and C2D: C2 interface used to program the micro-controller. C2CK is the clock pin and C2D is the data pin.
• RX and TX: UART serial interface used to interact with the firmware. Commands can be sent to RX pin using a serial terminal or another micro-controller, and data is output to the TX pin.
• Coil 1 and Coil 2: external coil. Polarity is not important.
• LED: - blink a LED when a tag is detected. The pin will be pulled to ground to turn on the LED so the LED must have the other pin pulled to VCC through a resistor (~1k). At the moment this is not implemented in the custom firmware.
• GND and Ush pin near the LED: not sure what these are for but you can see them in the schematic. Can be left unconnected.
  

RDM6300 v2 schematic (click to enlarge)

Programming RDM6300 with a custom firmware

The firmware can be replaced using a commercial programmer from Silicon Labs or a custom made one. To make a custom C2 programmer you only need an AVR328PB with an USB to serial converter. I have made an in depth tutorial here: https://www.programming-electronics-diy.xyz/2024/03/c2-programmer.html.

The custom programming interface can also be used to interact with the RDM6300 and read data from it, by selecting the Serial mode. Works on Linux and Windows.

Backing up the original firmware

If for some reason you want to use the module with the original firmware, you can do so by uploading the original firmware from the download section.

Flashing the micro-controller

To flash the micro-controller with the custom code use a programmer of your choice and the compiled hex file in the download section. In case you want to modify the code you will need the Simplicity Studio IDE. It's free. To compile the code you will need to sign up for a Keil license which is also free. If you don't know how to use Simplicity Studio, you can find some on this blog.

RDM-6300 API (Application Interface)

When a tag is successfully read, the module will automatically output the default frame.

Default frame format

Default frame consists of two field types, separated by ',' and terminated by a null character '\n'. The frame is repeated according to the corresponding setting (default 4).

Field type 1: integer representing the tag type

• 1: EM4100
• 2: T55xxCOMP - T55xx ICs that are set to be compatible with EM4100 readers
• 3: T55xx
  

Field type 2: tag data that depends on the tag type

• EM4100 and T55xxCOMP: 8-bit version/client ID, 32-bit tag number
• T55xx: 32-bit block. The number of blocks depends on the tag configuration. Most often is 2.

Examples:

03 - T55xx tag type, FFFB0000 - block 1, 00356244 - block 2 in hex format

03,FFFB0000,00356244

01 - EM4100 tag type,  00 - client ID, 79178B56 - tag number in hex format

01,00,79178B56

API data type

 

Output data

All numerical values are returned in HEX format. The reason for this is the space constraint. Since the UART is 8-bit, sending a larger value requires converting the integer to an ASCII string to represent the number and that function takes a lot more flash memory space than converting the integer to ASCII string but in hex format.

Input data

The API expects all input numbers to be an ASCII string since this is again a much more cost effective way regarding memory space.

Serial Commands

A command frame consists of a command number in an ASCII string format, followed by arguments. The command and arguments are separated by ':'. Arguments are separated by ','. End of frame is represented by the null character '\n'.

Command list

These should be copied from rdm.h to ensure they are up to date.

#define CMD_READ_TAG			"0"
#define CMD_READ_INFO			"1"
#define CMD_READ_PAGE			"2"
#define CMD_READ_BLOCK			"3"
#define CMD_READ_BLOCK_PWD		"4"
#define CMD_WRITE_BLOCK			"5"
#define CMD_WRITE_BLOCK_PWD		"6"
#define CMD_RESET			"7"
#define CMD_AOR				"8"
#define CMD_READ_CONF			"9"
#define CMD_READ_CONF_PWD		"10"
#define CMD_W_CONF_MASTER_KEY		"11"
#define CMD_W_CONF_BIT_RATE		"12"
#define CMD_W_CONF_XMODE		"13"
#define CMD_W_CONF_MODULATION		"14"
#define CMD_W_CONF_PSK			"15"
#define CMD_W_CONF_AOR			"16"
#define CMD_W_CONF_OTP			"17"
#define CMD_W_CONF_MAX_BLOCK		"18"
#define CMD_W_CONF_PWD			"19"
#define CMD_W_CONF_MARKER		"20"
#define CMD_W_CONF_FAST_WRITE		"21"
#define CMD_W_CONF_INVERSE_DATA		"22"
#define CMD_W_CONF_POR_DELAY		"23"
#define CMD_READ_DESCRIPTION		"24"

 

Read Tag (CMD_READ_TAG)

Read tag ID.

Usage:

UART_sendInt(0); // send command 0

 

Read traceability data (CMD_READ_INFO)

The two 32-bit blocks are formatted and returned as follows:

• ACL (8-bits)
  
• MFC (8-bits)
• ICR - IC revision (8-bits)
• ICR - customer ID (8-bits) 
• LotID (32-bits)
• DPW - wafer number (8-bits)
• DPW - die on wafer number (32-bits)

Example of returned data: E0,39,00,00,000D0D25,19,00005B03

Usage:

UART_sendInt(1); // send command 1

 

Read page (CMD_READ_PAGE)

Arguments:

1. page number

Return:

Returns block data within a page. Number of blocks are defined by the IC configuration register (default 2).

Usage:

2:1 // send command 2 to read page 1

 

Read block (CMD_READ_BLOCK, CMD_READ_BLOCK_PWD)

Direct reading a block within a page. If the password is active use the CMD_READ_BLOCK_PWD command.

Arguments:

1. page number
   
2. block number
3. password (only when CMD_READ_BLOCK_PWD is used)

Return:

Returns data from the requested block.

Usage:

3:0,2 // send command 3 to read block 2 from page 0 

4:0,2,1234 // send command 4 to read block 2 from page 0 using the secure password 1234

Write block (CMD_WRITE_BLOCK, CMD_WRITE_BLOCK_PWD)

Write a block within a page. When the password is active, use the CMD_WRITE_BLOCK_PWD command.

Arguments:

1. page number
2. block number
3. lock bit: 0 or 1. If 1, the block will be read-only.
4. data (32-bit): what to write.
5. lock bit again: same lock bit but sent twice to avoid user error that could lock the tag.
6. password (only when CMD_WRITE_BLOCK_PWD is used)
   

Usage:

5:0,1,0,5577,0 // send command 5 to write 5577 on block 1 from page 0 

6:0,1,0,5577,0,1234 // send command 5 to write 5577 on block 1 from page 0 using the most secure password 1234

Reset (CMD_RESET)

Sends the reset command to the tag.

AOR (CMD_AOR)

When AOR (Answer On Request) mode is active, use this command to activate the tag, by sending the given password.

Arguments:

1. password
   

Usage:

8:1234 // send command 8 and the 1234 password to activate the tag

Read configuration register (CMD_READ_CONF, CMD_READ_CONF_PWD)

Register data is formatted and returned in the following format. Each field is maximum 8 bits and separated by ','

• Master key
• Data bit rate
• Extended bit
• Modulation
• PSK-CF
• AOR
• OTP
• Max block
• PWD
• ST (Sequence Terminator)
• Fast write bit
• Inverse data bit
• POR delay
  

Note: due to limited space, the function is commented out. A workaround is to read the block 0 directly then use the code inside the rdm_t55xx_parseConfig function to parse the 32-bit value configuration register.

Read tag description (CMD_READ_DESCRIPTION)

Returns more info about the tag. Might be expanded in the future.

Return:

Returns human readable info.

• "RF/xx": Data bit rate, such as RF/16, RF/32, RF/64. This value is calculated based on the pulse duration an it can be off by 1 or 2. For example instead of 64 might be 65 or 63. This is useful when the configuration register cannot be read initially when the password is active, since the password in not known by the module.
  
• "ST:n": ST (Sequence Terminator) bit where n can be 0 or 1.
  

Write configuration register

The configuration register can be written using the block write command, however, unless you have some pre-calculated values this method leaves room for user error. Using this function, each setting can be modified individually by first reading the register, modifying the desired field value and writing the modified register back to the tag.

Available commands:

• CMD_W_CONF_MASTER_KEY
• CMD_W_CONF_BIT_RATE
• CMD_W_CONF_XMODE
• CMD_W_CONF_MODULATION
• CMD_W_CONF_PSK
• CMD_W_CONF_AOR
• CMD_W_CONF_OTP
• CMD_W_CONF_MAX_BLOCK
• CMD_W_CONF_PWD
• CMD_W_CONF_MARKER
• CMD_W_CONF_FAST_WRITE
• CMD_W_CONF_INVERSE_DATA
• CMD_W_CONF_POR_DELAY

There are no equivalent commands for when the password is active. If the password is active, set the password argument with a value other than 0.

Note that when setting the Bit Rate, the configuration data value argument must be according to the register shown in the datasheet and not the actual bit rate. For example, for RF/32 the value would be 2 and not 32, for RF/64 the value is 5 not 64, etc.

Arguments:

1. lock bit
2. configuration data: maximum 8 bits
3. password: if the password is not active, set this argument to 0
4. lock bit again

Usage:

19:0,1,0,0 // send command 19 to set the PWD (password) bit to 1. Lock bit and password are 0.

12:0,2,0,0 // send command 12 to set the bit rate 32. Lock bit and password are 0.

Download

Changelog and license can be found at the beginning of the header files
	RDM6300 code	Folder including: - Original firmware (HEX) - Custom compiled firmware (HEX) - Source code
Changelog
v1.0	06-07-2024: - public release

How to use Kodi with SMB on Windows 10 (and wireless printer on wired PC)

With latest versions of Kodi, SMB protocol is not as easy to set up as once was. I spent a day trying to figure out how to make sharing over SMB work with Kodi. I have seen advises saying that the SMB version should be changed to SMB v1 in settings but that was not necessary in my case - default settings works. There are many reasons that could prevent file sharing over SMB and I'm no expert, but I will show the steps I took in order to make things work.

Following steps are also useful for when a wireless printer is not accessible by a wired computer. 

Contents

• Router AP Isolation
• Sharing files in Windows 10
• Viewing shared folders in Network Explorer
• Using the Private Network profile
• Third-party app SMB confirmation
• Assigning a Static IP
• Accessing shared folders over SMB in Kodi
• Configuring TV remote to work with Kodi on Android TV

 

Router AP Isolation

If you have a NAS or simply use a Windows PC to share files using SMB, you first need to make sure that the wired devices can communicate with wireless ones. AP isolation is a feature that prevents your wireless devices from connecting to other networks. It can protect your network from other wireless networks and also protect it from infected devices. This can be disabled in the router settings. In my case I have an ONT router type so I had to contact the ISP and ask them to disable this separation.

Weird router behavior

With my ONT Fiberhome router provided by my ISP Digi there is one more thing to keep in mind. After the router is rebooted, the AP isolation is re-activated. What I have to do then is, turn off the router, unplug the fiber optic cable, turn on the router, wait for the red led to blink and then with the router on, plug the cable back on. Perhaps this setting is removed from memory and when the above steps are made, the setting is reloaded from ISP server.

Check if AP Isolation is off

I use two methods to verify if devices can see each other. First, make sure that the wireless device used is using the local wireless AP to access the internet and not the mobile data.

#1 - Wireless printer: if you have a wireless printer that works on wireless devices, turn it on and get its IP from router LAN - DHCP clients list. With my Brother printer I can connect to it using the IP address in a browser. If the wireless printer web page can be accessed from a wireless device, the printer works. If cannot be accessed from wired device such as a PC, the AP isolation is on.

#2 - Using Snapdrop: if you don't have a wireless printer you can use Snapdrop. Open the link in  browser on a wireless device and on a wired one. Say on a phone and a PC. If you can send a text message between them then AP Isolation is off.

Sharing files in Windows 10

To share a folder in Windows, simply right click on it and open the Properties window. In the Sharing tab click Share... In the share section you can add another account or just write Everyone then click Add.

To remove a shared folder use Advanced Sharing and uncheck Share this folder.

Next click on Network and Sharing Center and for Private network Turn on network discovery and check Turn on automatic setup of network connected devices.

Finally in All Networks there are the following settings:

- Public folder sharing (optional)

- Media streaming: I have not used this

- Password protected sharing: if on you must provide the account password when using SMB sharing. I turned of the password here.

Viewing shared folders in Network Explorer

Before checking the shared folders in Kodi, we need to make sure they appear in Windows Explorer under Network.

There should be something like this. If not click refresh and wait around 20 seconds to see if the computer name appears. If not press windows key, type Services and open it from the results. There look for Function Discovery Provider Host and Function Discovery Resource Publication. Make sure both are running and set to Automatic. 

If they are running select Function Discovery Resource Publication and in the left-hand side click on Restart. Now the computer name should appear in the Network Explorer. If not you can try other troubleshooting methods mentioned here: https://learn.microsoft.com/en-us/troubleshoot/windows-client/networking/cannot-access-shared-folder-file-explorer.

Using the Private Network profile

This next step is to ensure that you are using a Private network profile by right clicking on the Network icon in the right-hand corner and selecting Open Network and Internet Settings.

There should say Ethernet - Private network.

Otherwise switch to a private profile using the Ethernet menu, then click on Network and in the Network page select Private profile.

Third-party app SMB confirmation

An easy way to check if SMB sharing works is by using an app on Android phone called File Manager by Lufick. There, in the top left corner open the menu and under the Network section open Lan (SMB 2.0). In the bottom right corner tap on the 3 dots then on Start Scan. If everything is set up properly, the computer name and local IP should appear.

Assigning a Static IP

For the final step to work, the PC must have a static IP address on the LAN. For example, my router address is 192.168.1.1 in the Local Area Network so for my PC I have allocated the address 192.168.1.100 because it's easier to remember. This step is router dependent so I cannot show a step-by-step guide. The idea is that you need to find your MAC address of your PC and on the router you associate this MAC address with the desired static IP.

The computer MAC address can be found in Windows Settings - Network & Internet - Ethernet - Network - Properties - Physical address (MAC).

On the router look for DHCP Static Leases or if your router is different search online on where is this feature located.

Accessing shared folders over SMB in Kodi

Using Kodi is out of the scope of this tutorial, so I will not go in to too many details about the interface. That being said, let's add the shared folder in Kodi by browsing for the video source.

In my case, using Windows network (SMB) didn't show up the shared computer name so i had to use Add network location option. Windows network (SMB) option only worked when Kodi was installed on the same computer.

In the Add network location window put your IP address of the server/PC, the username that has access to the shared folders (in my case is Everyone) and the password associated with the user name account. If the account has no password or the password sharing is off, you still need to write something in the password field. I put 1234. It can be anything. After clicking OK, the source should now be ready to use.

After selecting it, you can give it a name.

To add source to library, open the source and right click on the shared folder to bring up the context menu where you can use Scan to library.

Configuring TV remote to work with Kodi on Android TV

Initially on my TV, the remote controller didn't work with Kodi which was asking to configure it but I couldn't since it didn't work thus, to configure the remote I used an USB mouse.

To attach a controller in Kodi, go to Settings - System - Input - Configure attached controllers.

As a controller profile I have used Kodi for the TV remote. There is a profile named TV Remote using the Get more... button but it didn't have all the functions I needed. Here is how I mapped the Kodi profile to buttons on the TV remote:

• A - center button (the one surrounded by arrows on remote)
• B - back button
• X - menu (used to access contextual menu on Kodi)
• Up, Down, Left, Right - to same buttons on the remote
  

That's it. Share if you found this helpful.

Simplicity Studio and Keil 8051 compiler issues and tutorial

Working with Simplicity Studio and Keil compiler can be frustrating sometimes. Most of the issues encountered were difficult to solve because the error messages given by the Keil compiler were very confusing. Thus, I will post here the most common issues that I've came across in the hope it will help others and perhaps me in the future.

Contents

• Keil Error Messages
• missing ';' before
• left side of asn-op not an lvalue
• syntax error near 'data type', expected '__asm'
• syntax error near '=', expected 'id'
• Keil no error issues
• Case #1
• Simplicity Studio Shortcuts
• Simplicity Studio 5 Tutorial
• Adding a product (device)
• Creating a new project
• Adding Shortcuts - Key Binding in Simplicity Studio v5
• Adding external files in Simplicity Studio
• Annotations in Simplicity Studio

 

Keil Error Messages

A list of Keil error codes and their description can be found here: https://developer.arm.com/documentation/101655/0961/Cx51-User-s-Guide/Error-Messages/Errors-and-Warnings/Reference. However, below are scenarios in which the error message and the cause are not related. For example when actually missing a ';' the error message is: syntax error near 'token', expected ';' but when something is not defined because an include file is missing, the error message is: missing ';' before.

missing ';' before

One might think this is obvious - you missed an ';' somewhere. But this is not always the case.

Scenario: error line appears when including a header file.

Solution #1: include SFR declarations in the header file according to the type of the device.

#include <SI_C8051F330_Register_Enums.h>

Solution #2: include stdint.h that defines integer types.

#include <stdint.h>

Solution #3: include stdbool.h.

#include <stdbool.h>

It appears that Keil shows the same error message when a data type is not defined.

 

left side of asn-op not an lvalue

Scenario:

uint64_t test_var = 0;
test_var = 1;

Cause:

Looking at the uint64_t definition in stdint.h reveals the problem:

typedef uint32_t uint64_t[2];

uint64_t is defined as an array of two uint32_t elements so test_var in the example should be used as an array: test_var[0] and test_var[1]. 

 

syntax error near 'data type', expected '__asm'

Solution: all variables must be defined before any other code.

syntax error near '=', expected '<id>'

Scenario:

uint16_t data = 0;

Solution: i believe data is a reserved keyword. Replacing the variable name with data_x solves the issue. The message 'data is a reserved keyword' should have been used. 

 

Keil no error issues

There are times when you might want the compiler to raise an error message or a warning but it doesn't.

Case #1

 

uint32_t data_x = 0;
data_x = (1 << 31);

This will not make the MSB a one. The 1 should be typecast  (uint32_t)1 << 32. 

 

Simplicity Studio Shortcuts

Here is a list of tips & tricks that can help improve productivity in Simplicity Studio.

1. Delete a line: CTRL + D
2. Duplicate a line: CTRL + ALT + DOWN 
3. Highlight all occurrences of a variable: double click it
   
4. Go to last edited line: CTRL + Q
5. Switch between .h and .c files: CTRL + TAB
6. Next annotation: CTRL + .
7. Previous annotation: CTRL + ,
8. Navigate to previous line history: ALT + LEFT and ALT + RIGHT
9. Go to where is declared or defined: place cursor on a variable or function name then F3.
10. Comment/Uncomment: toggle comment selected line(s) using CTRL + /
11. Block Comment/Uncomment using: toggle comment selected line(s) using CTRL + SHIFT + /
12. Zoom Out text: CTRL + -
13. Zoom In text: CTRL + SHIFT + +
14. Renaming: SHIFT + ALT + R. Sometimes doesn't rename all occurrences. In that case undo, and try again. Saving all files first, might help.
    
15. Quick Utility: not sure how it's called but by pressing ALT + SPACE you can invoke some plugins. For example starting the expression with = you can do math.
16. Content Assist: CTRL + SPACE. Autocompletes or offers a list of suggestions while typing. So if you don't know the name of a function or variable but you remember first characters this can help finding it faster. 
17. Correct Indentation: CTRL + I
    

 

Simplicity Studio 5 Tutorial

Adding a product (device)

Press on the Welcome or Launcher button then in My Products section use the + button to add a new product.

On the next window you can search for Kits, Boards and Parts. In this example I use the C8051F330 microcontroller so I have added it in the right side.

At the end, by selecting the added product you can find in the right side, code examples, documentation and compatible tools. Configuration wizard under the compatible tools is worth checking out.

Creating a new project

Under File → New → select Silicon Labs Project Wizard

Next you can search for a board or if you are using a custom board search for target device - the microcontroller. In my case the device is C8051F330. The SDK and Toolchain should also be installed and selected.

In the next step you can use an example project or create an empty C project. The Configurator Project can be used to generate code using a graphical interface but is not available for all microcontrollers. Trying to create a configurator project for C8051F330 will result in an error. I did use it with EFM8 and worked very well.

Finally chose the project name and location. I recommend changing only the project name and leaving the rest as defaults.

Adding Keyboard Shortcuts - Key Binding in Simplicity Studio v5

In this example lets add a keyboard shortcut for building the selected project. This can be done in Windows → Preferences → General → Keys.

First search for the desired command, for example 'build' then select 'Build Project' from the search results. In the Binding input press the key or key combination. If the binding is already used elsewhere, it will appear in the Conflicts box.

Adding external files in Simplicity Studio

Linking to external files is useful when you need a library for example and if you update it you don't have to remember to update all files copied in other projects. Including external files can be done in two steps.

First drag-and-drop the files in the src folder located inside the project folder.

Then in the following dialog select 'Link to files'.

Last step is to add the include paths in Project Properties → C/C++ Build → Settings → Tool Settings tab → Keil 8051 Compiler → Includes. Here press the + green button then on File system to select the folder where the files included by drag-and-drop are located.

In this example I have included the folder containing the uart library files and the folder where utils files are that are included by uart library. 

Annotations in Simplicity Studio

An annotation in Simplicity Studio can be a part of many categories such as: bookmarks, breakpoints, info, errors, etc. They can be navigated using the shortcuts CTRL + , and CTRL + . or by using the up and down arrows on the toolbar. They are also highlighted with different colors on the right side bar near the scrollbar. Contrast and colors can be changed by right clicking on the same bar.

You can enable or disable what is included in annotations category while navigating them. Simply click on the down arrow near any of the annotation buttons on the toolbar to select only what you are interested in.

In case the buttons don't appear, right click on the toolbar and select Restore Hidden Toolbar Entries, then Lock the Toolbars then Unlock the Toolbars. Now the buttons should be visible.

You can add your own annotations such as a bookmark or a task by right clicking on line numbers in the left side bar.

To remove them, right click an annotation and select Remove bookmark or task.