Rpi4B and Midas 10" 1280 x 800 HDMI Monitor Interface Problem

Question

I have a raspberry pi 4 using the latest Os but I cant get anything to display on my monitor the monitor I am using is MCT101HDMI-A I have tried another monitor and it display works so I know nothing wrong with the Pi or the SD card as i can also SSH into it.

My config.txt setting are currently:

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87

hdmi_cvt=1280 800 60 5 0 0 0

#hdmi_timings=1280 0 16 44 100 800 0 10 3 10 0 0 0 60 0 71000000 7

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=7

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
start_x=1
gpu_mem=128

Answer 1

Question

How can Rpi4B talk to Midas 10" I2C CTP/RTP TFT HDMI monitor MCT101HDMI-A?

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Answer

It appears that you need to connect three cables from Rpi to HDMI monitor, not just one HDMI cable, as for ordinary HDMI monitors. I guess this is because you monitor has a touch screen, so is actually a HAT, with 40 pins connected to Rpi.

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References

(1) Midas 10" I2C CTP/RTP TFT HDMI monitor MCT101HDMI-A User Guide

(2) 4 Easy Steps To Raspberry Pi Connection - Midas Displays 2018

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Appendices

Appendix - Rpi4B Bootloader

Checking/Updating the bootloader (sudo apt install rpi-eeprom)

We recommend setting up your Pi so that it automatically updates the bootloader: this means you will get new features and bug fixes as they are released. Bootloader updates are performed by the rpi-eeprom package, which installs a service that runs at boot-time to check for critical updates.

Appendix B - Rpi config.txt readme

The Raspberry Pi uses a configuration file instead of the BIOS you would expect to find on a conventional PC. The system configuration parameters, which would traditionally be edited and stored using a BIOS, are stored instead in an optional text file named config.txt. This is read by the GPU before the ARM CPU and Linux are initialised.

It must therefore be located on the first (boot) partition of your SD card, alongside bootcode.bin and start.elf. This file is normally accessible as /boot/config.txt from Linux, and must be edited as root. From Windows or OS X it is visible as a file in the only accessible part of the card. If you need to apply some of the config settings below, but you don't have a config.txt on your boot partition yet, simply create it as a new text file.

Any changes will only take effect after you have rebooted your Raspberry Pi. After Linux has booted, you can view the current active settings using the following commands:

vcgencmd get_config : this displays a specific config value, e.g. vcgencmd get_config arm_freq.

vcgencmd get_config int: this lists all the integer config options that are set (non-zero).

vcgencmd get_config str: this lists all the string config options that are set (non-null).

Note that there are a few config settings that cannot be retrieved using vcgencmd.

File format The config.txt file is read by the early-stage boot firmware, so it has a very simple file format. The format is a single property=value statement on each line, where value is either an integer or a string. Comments may be added, or existing config values may be commented out and disabled, by starting a line with the ... character.

Here is an example file:

Force the monitor to HDMI mode so that sound will be sent over HDMI cable hdmi_drive=2

Set monitor mode to DMT hdmi_group=2

Set monitor resolution to 1024x768 XGA 60Hz (HDMI_DMT_XGA_60) hdmi_mode=16

Make display smaller to stop text spilling off the screen

overscan_left=20 overscan_right=12 overscan_top=10 overscan_bottom=10 config.txt Options

A range of options can be specified using the config.txt file. These are split into different sections, indexed below:

Memory

Licence Keys

Codecs Video

Display

Audio

Camera

Boot

Ports

Device Tree

GPIOs

Overclocking

Conditional Filters

Miscellaneous

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