Chroma Series SubGhz Tags - OpenEPaperLink/OpenEPaperLink GitHub Wiki

Currently the following tags are supported:

Tag	SN Format	Display Type	Binary filename
Chroma29	"JA0xxxxxxxB" or "JA1xxxxxxxB"	BWR	chroma29_<type>_<version>.bin
Chroma29	"JA1xxxxxxxC"	BWR	chroma29_8151_<type>_<version>.bin
Chroma42	"JC0xxxxxxxB"	BWR	chroma42_<type>_<version>.bin
Chroma42	"JH1xxxxxxxB"	BWY	chroma42_8176_<type>_<version>.bin
Chroma74	"JM1xxxxxxxB"	BWY	chroma74y_<type>_<version>.bin
Chroma74	"JL1xxxxxxxB"	BWR	chroma74r_<type>_<version>.bin

Where <type> is either "full" or "ota" and <version> is the 4 digit firmware version in hex for example "chroma29_8151_full_0012.bin"

Binaries are available here: https://github.com/OpenEPaperLink/OpenEPaperLink/tree/master/binaries/Tag .

Refer the table above for the correct filename.

Source code is available here.

Unlike other tags the test points needed to flash custom firmware are not accessible on most Chroma tags without opening the case.

The test points needed for flashing are labeled by the silk screen and should be easy to locate.

The case is fairly easy to open and if it is opened carefully it is unlikely to be damaged.

Carefully prying the white front away from the gray back starting at a corner is the easiest.

After programming the case can be easily snapped back together.

After the TAG is flashed and reset the OpenEPaperLink splash screen should be displayed.

For example:

All of the Chroma series of tags support three colors, either black, white, and red (BWR) or black, white, and yellow (BWY).

It is suspected that the first two letters of the SN indicate if the display is BWR or BWY, details here.

All of the Chroma series of tags support three colors, either black, white, and red (BWR) or black, white, and yellow (BWY).

It is suspected that the first two letters of the SN indicate if the display is BWR or BWY, details here.

Model	Screen size	Resolution	EEPROM size	Supported
Chroma 16	1.08 x 1.08 in	152 x 152	128K	N
Chroma 21	1.9 x 1.00 in	212 x 104	128K	Planned
Chroma 27	2.4 x 1.20 in	296 x 152	128K	N
Chroma 29	2.6 x 1.10 in	296 x 128	128K	Y
Chroma 37	3.2 x 1.85 in	416 x 240	?	N
Chroma 42	3.3 x 2.50 in	400 x 300	1024K	Y
Chroma 60	4.7 x 3.50 in	600 x 448	1024K	maybe
Chroma 74	6.4 x 3.50 in	640 x 384	1024K	Y
Chroma 74H+	6.4 x 3.90 in	800 x 480	1024K	Port in process
Chroma Aeon 74	6.4 x 3.90 in	800 x 480	1024K	Port in process
Chroma 125	10.0 x 7.50 in	1304 x 984		N

The displays with support marked as "N" means that no one (or at least no developer) has any.

The displays with support marked as "maybe" means that there isn't a sufficient supply currently to make it worth the effort.

All of the older Chroma tags used the same basic design based on the TI CC1110 SOC with an 26Mhz 8051 MCU, 32kB of Flash and 4kB of RAM. It is likely that only the EPD driver will need to be changed to support additional models based on the CC1110 SOC.

The newer Chroma tags have replaced the legacy CC1110 SOC with a newer ARM Cortex M3 based CC1310F64 SOC or CC1311R3 SOC. So far these newer version of the Chromas are rare. A porting effort for CC131x based tags is underway.

There are several ways to flash the firmware:

1. The TI CC-Debugger or an inexpensive clone.
2. ATC1441's ESP_CC_Flasher, video.
3. Rpi based flash_cc2531.
4. Rpi based cc1110-prog.
5. OEPL Tag-Flasher.

There are probably other options, please feel free to add them to the Wiki !

All flashing methods require 4 wires: GND, DC, DD and Reset_n.

Signal	Test point
GND	TP8 or TP18
+VBAT	TP4 or TP14
DC	TP5 or TP15
DD	TP3 or TP13
Reset_n	TP2 or TP12

Note: Test points TP10 and above are on the top/component side of the PCB the rest are on the other side.

If you go the CC-Debugger route you can use TI Windows based app.

If you run Linux cc-tool works well.

Signal	Test point	CC debugger pin
GND	TP8 or TP18	1
+VBAT	TP4 or TP14	2
DC	TP5 or TP15	3
DD	TP3 or TP13	4
Reset_n	TP2 or TP12	7

The TI programmer requires the target's +VBAT to be connected for level translators.

NB: The LED on the CC-Debugger should be green if it detects the CC1110.

The CC-debugger only looks for the chip when first connected to USB or when the reset switch is clicked. If the LED is red try clicking the reset button, if that doesn't turn the LED green then check your wiring.

If you like you can jumper pins 2 and 9 on the CC-Debugger to power the tag from the debugger to prevent having to have batteries installed while programming.

A programmer with cJTAG support is needed to program CC131x based tags.

The least expensive option currently known is this TI debugger.

Note: Many TI evaluations boards include a debugger which can also be used. Make sure the embedded debugger is XDS110 compatible.

If you know of other options please ADD them here please and let us know!

flashing requires 4 wires: GND, TSMC, TCKC and Reset_n.

Signal	Test point
GND	TP8 or TP18
+VBAT	TP4 or TP14
TSMC	TP5 or TP15
TCKC	TP3 or TP13
Reset_n	TP2 or TP12

During initial configuration Chroma tags search for APs on all supported channels in both the 868 MHz band and the 915 Mhz band. Once an AP is detected the AP's channel and band are saved with the tags settings.

On subsequential resets the last channel is checked for an AP and a scan is only performed if the AP is not detected. Scans are then restricted to channels in the configured band.

This behavior minimizes power consumption and out of band operation.

The tag's settings must be cleared to change bands after the tag is configured.

Connecting a serial port to the Chroma is very handy for development but it is not needed if you just want to flash custom firmware.

The serial port's baudrate is 115200, 8 data bits and no parity.

A serial interface compatible with 3v logic levels is required, a 5V cable MAY cause problems, RS232 levels WILL probably destroy the tag.

An a FTDI TTL-232R-3V3 is one example, while somewhat expensive it works flawlessly on many operating systems and supports a wide range of baudrates.

Test point	Signal	FTDI
J3	GND	Black
TP7 or TP17	Serial out Chroma -> PC	Yellow
TP9 or TP19	Serial out PC -> Chroma Optional	Orange

The tag's serial number (SN) is printed on the label on the back of the tag and in barcode format on the label and the front or side of the display.

The SN has 11 characters consisting of 2 letters, 8 digits and one letter. For example "JM10339094B".

The first two letters of the SN appear to indicate the model of the display including if the display is BWR or BWY.

First 2 Letters	Model	Notes
GA	EPOP900	Older LCD type, not an EPaper display
JA	BWR Chroma 29
JB	BWR Chroma 21
JC	BWR Chroma 42
JD	BWR Chroma 60
JF	BWY? Chroma 29
JG	BWY Chroma 21
JH	BWY Chroma 42
JJ	BWR? Chroma 60
JK	BW? Chroma 16
JL	BWR Chroma 74
JM	BWY Chroma 74
JN	BWR Chroma 37
KA	BW Aura 29
KD	BW Aura 42
LD	Chroma 21	CC1310 SOC
ME	Chroma 29	CC1310 SOC
MJ	Chroma 21	CC1310 SOC
MS	Chroma 74H+	CC1310 SOC
SR	BWY Chroma Aeon 74	CC1311 SOC

The first digit appears it indicate if the TAG includes hardware support for disconnecting power from the EPD when it is not being used.

Digit	EPD power disconnect
0	No
1	Yes

The next 7 digits are an unique per tag identifier.

The last character seems to indicate the version of the RF protocol spoken by the display.

The SN is programmed into the SPI flash during manufacture with the possible exception of the last character.

Since the OEPL uses the 8 byte extended address specified by IEEE 802.15.4 and the serial number is only 6 bytes the most significant 2 bytes of the extended address are fixed (0x44 0x67).

Model	Resolution	Tag Type (HW_ID)	Base Type
Chroma 29	296 x 128	0x82	0x01
Chroma 42	400 x 300	0x83	0x02
Chroma 74	640 x 384	0x80	0x05
Chroma Aeon 74	800 x 480	0x81	0x36