Kuman SC3A-1 (MAR3501) working on UNO but stopped working on Mega2560

I'm very new here...

I have a Kuman SC3A-1 320x480 lcd/touch/sd display shield with ILI9486 lcd controller.
I am using the MCUFRIEND_kbv library that shipped with the shield.
The shield works fine on a UNO, and the LCD had also been working fine on my Mega2560 until recently.
Now I'm just getting a white screen and failure to initialize or write to the lcd.
(the touchscreen is still working on both the UNO and the Mega)

The LCD_ID_readreg output for both is pasted below (sorry for the timestamps...)
The D3 values don't appear to be correct on the Mega, but I have no idea how/what modifies them.

I'm getting "reg(0x00D3) 00 12 40 00" on the Mega, but on the UNO reg D3 reports the expected "reg(0x00D3) 00 00 94 86".

What am I missing here?

-dave


Mega2560 registers:

18:04:22.520 -> reg(0x0000) 00 00 ID: ILI9320, ILI9325, ILI9335, ...
18:04:22.520 -> reg(0x0004) 00 03 03 03 Manufacturer ID
18:04:22.554 -> reg(0x0009) 00 00 00 00 00 Status Register
18:04:22.622 -> reg(0x000A) 00 04 Get Powsr Mode
18:04:22.656 -> reg(0x000C) 00 00 Get Pixel Format
18:04:22.690 -> reg(0x0061) 00 00 RDID1 HX8347-G
18:04:22.724 -> reg(0x0062) 00 00 RDID2 HX8347-G
18:04:22.758 -> reg(0x0063) 00 00 RDID3 HX8347-G
18:04:22.791 -> reg(0x0064) 00 03 RDID1 HX8347-A
18:04:22.825 -> reg(0x0065) 00 30 RDID2 HX8347-A
18:04:22.859 -> reg(0x0066) 00 00 RDID3 HX8347-A
18:04:22.893 -> reg(0x0067) 00 0C RDID Himax HX8347-A
18:04:22.927 -> reg(0x0070) 00 00 Panel Himax HX8347-A
18:04:22.961 -> reg(0x00A1) 00 00 34 2B 03 RD_DDB SSD1963
18:04:23.029 -> reg(0x00B0) 00 00 RGB Interface Signal Control
18:04:23.063 -> reg(0x00B4) 00 00 Inversion Control
18:04:23.097 -> reg(0x00B6) 00 14 00 66 66 Display Control
18:04:23.164 -> reg(0x00B7) 00 A9 Entry Mode Set
18:04:23.198 -> reg(0x00BF) 00 00 00 00 00 00 ILI9481, HX8357-B
18:04:23.232 -> reg(0x00C0) 00 00 2D 3F 08 06 0E 03 0E Panel Control
18:04:23.300 -> reg(0x00C8) 00 04 44 44 44 44 44 44 44 44 44 44 44 GAMMA
18:04:23.368 -> reg(0x00CC) 00 00 Panel Control
18:04:23.402 -> reg(0x00D0) 00 00 00 Power Control
18:04:23.436 -> reg(0x00D2) 00 18 A3 12 02 NVM Read
18:04:23.470 -> reg(0x00D3) 00 12 40 00 ILI9341, ILI9488
18:04:23.504 -> reg(0x00DA) 00 00 RDID1
18:04:23.537 -> reg(0x00DB) 00 00 RDID2
18:04:23.571 -> reg(0x00DC) 00 00 RDID3
18:04:23.605 -> reg(0x00E0) 00 00 2D 3F 08 06 0E 03 0E 36 0F 0D 07 15 29 07 GAMMA-P
18:04:23.673 -> reg(0x00E1) 00 00 34 2B 03 01 07 3B EB 2F 05 19 0E 2F 13 08 GAMMA-N
18:04:23.742 -> reg(0x00EF) 00 80 00 10 60 40 ILI9327
18:04:23.776 -> reg(0x00F2) 00 18 A3 12 02 32 12 3F 10 00 00 00 Adjust Control 2
18:04:23.844 -> reg(0x00F6) 00 54 00 66 Interface Control


Same LCD shield on UNO R3 - Registers:

reg(0x0000) 00 00 ID: ILI9320, ILI9325, ILI9335, ...
reg(0x0004) 00 54 80 66 Manufacturer ID
reg(0x0009) 00 00 61 00 00 Status Register
reg(0x000A) 00 08 Get Powsr Mode
reg(0x000C) 00 66 Get Pixel Format
reg(0x0061) 00 00 RDID1 HX8347-G
reg(0x0062) 00 00 RDID2 HX8347-G
reg(0x0063) 00 00 RDID3 HX8347-G
reg(0x0064) 00 00 RDID1 HX8347-A
reg(0x0065) 00 00 RDID2 HX8347-A
reg(0x0066) 00 00 RDID3 HX8347-A
reg(0x0067) 00 00 RDID Himax HX8347-A
reg(0x0070) 00 00 Panel Himax HX8347-A
reg(0x00A1) 00 93 30 93 30 RD_DDB SSD1963
reg(0x00B0) 00 00 RGB Interface Signal Control
reg(0x00B4) 00 00 Inversion Control
reg(0x00B6) 00 02 02 3B 3B Display Control
reg(0x00B7) 00 06 Entry Mode Set
reg(0x00BF) 00 00 00 00 00 00 ILI9481, HX8357-B
reg(0x00C0) 00 0E 0E 0E 0E 0E 0E 0E 0E Panel Control
reg(0x00C8) 00 00 00 00 00 00 00 00 00 00 00 00 00 GAMMA
reg(0x00CC) 00 04 Panel Control
reg(0x00D0) 00 00 00 Power Control
reg(0x00D2) 00 00 00 00 00 NVM Read
reg(0x00D3) 00 00 94 86 ILI9341, ILI9488
reg(0x00DA) 00 54 RDID1
reg(0x00DB) 00 80 RDID2
reg(0x00DC) 00 66 RDID3
reg(0x00E0) 00 00 28 3F 08 06 0E 47 0E 36 0F 0D 07 0D 29 06 GAMMA-P
reg(0x00E1) 00 01 2B 2B 03 00 07 2B CB 2F 05 19 0E 2F 13 09 GAMMA-N
reg(0x00EF) 00 80 00 10 60 40 ILI9327
reg(0x00F2) 00 18 A3 12 02 B2 12 FF 10 00 00 00 Adjust Control 2
reg(0x00F6) 00 54 80 66 Interface Control

I have no idea what the Kuman pcb looks like.
Or whether they have hacked MCUFRIEND_kbv

If the pcb has not got an AMS1117-3.3 regulator chip, I would suspect that the Mega's 3.3V regulator has been destroyed.
The current mcufriend.com pcb is WRONG. Uno and Mega can only supply 50mA from the 3.3V socket.
I am surprised that more Uno and Mega owners have not destroyed their Arduinos.

Please post a link to your shield that shows an accurate photo of your pcb.
Please check your MCUFRIEND_kbv version via the IDE Library Manager.

David.

Thanks Peter.

I have uninstalled the Kuman library files and installed the current version of MCUFRIEND_kbv from the IDE’s Library manager. And I now have a new Mega2560 and the display is working on it, so apparently something has done damage to the other Mega somewhere along the line…

My project is using a home-spun serial interface to level-shift the 12-volt K-Line (ISO-14230 single line serial port) in my van’s OBDII port, but the serial ports and data pins on the damaged Mega are still functioning so I don’t think that is the source of the problem? The signal voltage from my interface board tops at 5.5 volts when there’s 14.2 volts on the K-Line bus, so I plan to adjust the 47k and 33k resistors on the incoming voltage divider to bring this level down to a 4 to 4.5 volt range?

The display shield’s LCD is foam taped to the pcb so I can only see the bottom (pin) side, but there don’t appear to be any components on the “top”. There are three ic’s on the bottom:
U3: “NXP / LVC245A / SA96855 / TXD739F”
U2: “NXP / LVC245A / SA96855 / TXD739F”
and a “AMS1117 3.3 DN711” (which has a trace to the 5v pin on the Arduino)

Photos attached,

-dave

Woo-hoo. LVC245 is the correct buffer. AMS1117-3.3 is the correct LDO regulator.
Your display should work safely with Uno or Mega (and every other Arduino).

There is no need for a photo. You have identified the components on the pcb.

What did the Library Manager say about the "Kuman" MCUFRIEND_kbv version?
The ILI9486 should work on the Mega even with obsolete versions.

I would still measure the voltage on the 3.3V pin of the Mega. Just to check that the Mega's regulator is ok.

David.

Well that's good news... thank you for vetting the shield.

Any comment on my interface driving the digital pins up to 5.5 volts?
Might that have damaged the Mega2560 in a manner that would prevent it from communicating with the display? The touch screen and SD interface remain functional...

-dave