Connectors
UM2271
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DocID030906 Rev 2
11.2.1 DSI
AMOLED
display
Warning:
Permanent image sticking may occur if AMOLED displays
same image for an extended period of time.
The DSI display is based on a round AMOLED Touch sensitive panel of 1.2 inch and
390x390 pixels. The display module reference is IEG1120TB103GF-001 from Govisionox
Optoelectronics. It displays up to 16M colors. The round DSI display module board
reference is MB1314. The DSI interface of MB1314 is only one data-lane width and a clock
lane, but the 32L4R9IDISCOVERY board supports DSI displays with up to two data-lane
width. The DSI_V3 connector interface also enables the use of dedicated low power modes
of display, thanks to the available SPI2 interface (MB1314 does not use it). It is also possible
to use some of USART3 signals to control a low power mode (SB6 and SB8 are respectively
exclusive with SB13 and SB7).
The DSI_TE signal PF11 is used as an input of the main microcontroller connected to the
display signal TE (tearing effect). DSI_TE signal is used to synchronize the refresh of the
display memory by the microcontroller with the display scan, this to avoid visible artefacts.
DSI_3V3_PWRON signal (MFX_GPIO8, low level active) controls the 3V3 level Power
supplies provided on the DSI_V3 connector interface. DSI_1V8_PWRON signal
(MFX_aGPIO2) controls the 1V8 level Power supplies provided on the DSI_V3 connector
interface. Both shall be used to enable or disable display, TP and PSRAM. They allows to
disconnect those peripherals when doing low power IDD measurement.
DSI_RESET signal (MFX_GPIO10, low level active) controls the reset for the display and
the Touch panel.
An optional DSI_SWIRE signal PA8 offers additional possibility to control the voltage for any
display supply during initialization (not used by MB1314 by default). PA8 is exclusive with
another function from 32L4R9IDISCOVERY board: CAMERA clock Interface (MCO), which
is the default setting.
11.2.2 Backlight
and
OLED power supplies generation
This function is handled by the Power driver circuit SM3321, included on the MB1314 DSI
display Board. SM3321 is a switching mode boost converter supplied by the 3V3 rail of the
DSI_V3 connector interface. SM3321 is controlled either by the AMOLED driver circuit itself
(default configuration), either by DSI_BL_CTRL (PB1) from main MCU, either from the
DSI_SWIRE (PA8) interface from main MCU. SM3321 provides all necessary voltage
references to AMOLED display.
If used, the signal DSI_BL_CTRL switches on the backlight with a high level. It is possible to
dim the backlight intensity by applying a low frequency PWM signal to DSI_BL_CTRL (1 to
10 kHz typically).
11.2.3 Touch
panel
The touch panel is a capacitive touch panel using an I2C interface. The touch panel IC
reference is FT3267, and is located on the MB1314 board. The FT3267 I2C1 default
addresses are 0x71 and 0x70.
