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IoD Display Module Series
GPIO0, GPIO2 or GPIO16 for the Chip Select for any
additional devices.
GPIO16 (User GPIO)
Input/Output available to the user. This pin can be
used as a digital input or digital output to connect to
sensors, relays etc. This pin can also be used for '1-
wire' protocol devices and as a PWM output, or it can
be used as the Chip Select for the SPI bus.
SPI
There is 1 hardware SPI channel (HWSPI) which is used
to drive the screen, and the SD card. The SPI channel
is capable to communicate at speeds up to 80Mhz. The
SPI channel is Master only, and can be used by the
User for additional SPI devices, however is shared with
the Display and the SD Card. An additional GPIO is
required for each additional SPI device to be added to
the bus, to act as Chip Select.
When communications to the Display are taking place,
the SPI bus must not exceed 39Mhz, due to this being
the maximum stable speed it can operate.
When communications to the SD card are taking place,
the SPI bus must not exceed 30Mhz, due to this being
the maximum stable speed it can operate. This may
need to be reduced further depending on the
capabilities of the SD card being used. This is
configurable in the GFX4dIoD09 library.
Note: The SPI channel (HWSPI) is dedicated to
memory card, and screen. The HWSPI channel cannot
be reconfigured for alternate uses, as Display and SD
card would then be inoperable.
I2C
I2C is available on the IoD-09, using GPIO0 and GPIO2.
Take note however that these pins must be left to be
pulled high during startup, in order for the ESP8266 to
boot correctly. Pull up resistors are present on the IoD-
09 so it boots correctly, which is also required for I2C.
The IoD-09 is compatible with 100kbit/s and 400kbit/s
bus speeds, (higher may be possible, refer ESP8266
documentation).
The TX and RX serial UART pins on the IoD-09
(ESP8266) are also compatible with I2C, if these are
desired to be used instead. No pull-up resistors are
built in to the IoD-09 for these pins.
1–Wire
1-Wire communications are available on GPIO0, GPIO2
or GPIO16, for communicating with Delas 1-wire
© 2017 4D SYSTEMS
compatible devices. A library for the IoD-09 has been
created to aid using this communication bus type.
ESP8266 SoC
The module is designed around the ESP8266 SoC from
Espressif.
The ESP8266 is a 32bit RISC Microcontroller with built
in WiFi controller, and GPIO capability, however some
GPIO are utilised for on board features, such as the TFT
LCD and microSD card.
The TFT-LCD display interfaces to the ESP8266 using
SPI, along with the microSD card. This enables high
speed transfers for these peripherals, providing fast
graphics and fast SD card access.
Powerful graphics, text, image, animation, internet
access and countless more features are available to
the user via the 4D Systems GFX4dIoD09 library and
4D Systems Workshop 4 IDE. Alternatively, the
Arduino IDE can be used, and the User is able to write
drivers/software for the module as they require.
SD/SDHC Memory Cards
The IoD-09 module supports microSD memory cards
via the on-board micro-SD connector.
The memory card is used for
all multimedia file retrieval
such as images, animations
and data files.
The memory card can also be
used
as
general-purpose
storage for data logging applications.
Support is available for off-the-shelf high capacity HC
memory cards (4GB and above). Memory cards up to
32GB is size can be used, as FAT16 or FAT32, however
it must be noted that only a portion of this can be
utilised by the FAT16 file system.
Page 9 of 22
IoD-09TH/SM
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