RT1050 FlexIO OV7670 with TFT LCDdisplay
1 Abstract
Regarding the RT10XX flexIO collecting OV7670 camera data and displaying it on TFT LCD, in fact, the NXP official website has a very good application note AN12686, but the test is based on RT1010 and not EVK. It may be difficult for actual customers to test directly. When the author was supporting customers, I encountered customers who wanted to implement flexIO on RT1050 EVK to collect parallel port OV7670 data and display it on TFT LCD, which is the LCD with SPI interface, so this article gives the specific test results of the finished product, RT1050 flexIO and There are some differences between RT1010 flexIO. RT1010 flexIO has 8 shifters, but RT1050 only has 4 shifters, so some code modifications need to be made and transplanted to RT1050. Since it is going to run on MIMXRT1050-EVKB, you also need to consider the flexIO pins that can be used, modify the EVKB, and manually weld the relevant pins to configure the corresponding camera signals and LCD display signals.
This article mainly comes from problems encountered by customers during testing, so it provides specific hardware connections, software code sharing, test finished product results, etc.
2. Software and hardware prepare
Since AN12686 has given the principle in great detail, this article aims to give the differences and the specific conditions of working on RT1050-EVKB.
2.1 Hardware configuration
The platform is based on MIMXRT1050-EVKB revA1, OV7670 module, 2.4-inch TFT LCD LCD SPI serial touch TFT color screen ILI9321, with a resolution of 240*320.
For the OV7670 module status and pin status, please check the article:
RT1050 CSI OV7670 camera eLCD display
The camera module pins are as follows:
Fig 1
TFT LCD picture：
Fig 2
|
Pin No |
Signal |
Description |
|
1 |
GND |
Power ground |
|
2 |
VCC |
Power 3.3V |
|
3 |
CLK |
SPI clock |
|
4 |
MOSI |
SPI data |
|
5 |
RES |
LCD reset |
|
6 |
DC |
LCD data/commander select pin |
|
7 |
BLK |
Backlight control switch, backlight is turned on by default, low level turns off the backlight |
|
8 |
MISO |
Touch data reading |
|
9 |
CS1 |
Display selection pin |
|
10 |
CS2 |
Touch selection pin |
|
11 |
PEN |
Touch interrupt signal |
For LCD, this article only uses the display part and does not use the rough mold part.
Considering the pin layout of MIMXRT1050-EVKB, the application note flexIO1 is not used here, but FlexIO2 is selected. The actual RT1050-EVKB and OV7670 module and LCD connection pins are given below.
The connection between the LCD signal pin and the MCU MIMXRT1050-EVKB RevA1 signal pin is as follows:
|
LCD signal and pin |
MIMXRT1050-EVKB revA1 signal and pin |
||
|
GND |
P1 |
GND |
J24_7 |
|
3.3V VCC |
P2 |
3.3V |
J24_8 |
|
CLK |
P3 |
GPIO_AD_B1_15(SPI3_CLK) |
R98 |
|
MOSI |
P4 |
GPIO_AD_B1_14(SPI3_MOSI) |
R99 |
|
RES |
P5 |
GPIO_AD_B0_02(GPIO1_IO02) |
J24_2 |
|
DC |
P6 |
GPIO_AD_B1_10(GPIO01_IO26) |
J23_1 |
|
CS1 |
P9 |
GPIO_AD_B1_12(GPIO01_IO28) |
R100 |
OV7670 signal pin and MCU MIMXRT1050-EVKB RevA1 signal pin connection situation:
|
0V7670 signal and pin |
MIMXRT1050-EVKB revA1 signal and pin |
||
|
OV7670_D0 |
P3 |
GPIO_B0_05(FLEXIO2_D05) |
SW5_1 |
|
OV7670_D1 |
P4 |
GPIO_B0_06(FLEXIO2_D06) |
SW5.2 |
|
OV7670_D2 |
P5 |
GPIO_B0_07(FLEXIO2_D07) |
SW5_3 |
|
OV7670_D3 |
P6 |
GPIO_B0_08(FLEXIO2_D08) |
SW5_4 |
|
OV7670_D4 |
P7 |
GPIO_B0_09(FLEXIO2_D09) |
SW6_1 |
|
OV7670_D5 |
P8 |
GPIO_B0_10(FLEXIO2_D10) |
SW7_1 |
|
OV7670_D6 |
P9 |
GPIO_B0_11(FLEXIO2_D11) |
SW6_2 |
|
OV7670_D7 |
P10 |
GPIO_B0_12(FLEXIO2_D12) |
SW6_3 |
|
XCLK |
P11 |
GPIO_B0_13(FLEXIO2_D13) |
SW7_2 |
|
PCLK |
P12 |
GPIO_B0_14(FLEXIO2_D14) |
SW6_4 |
|
HREF(HS) |
P13 |
GPIO_B0_15(FLEXIO2_D15) |
R258/R324 |
|
VSYNC |
P14 |
GPIO_AD_B0_03(GPIO01_03) |
J24_1 |
|
I2C_SDA |
P15 |
GPIO_AD_B1_01(I2C1_SDA) |
J23_5 |
|
I2C_SCL |
P16 |
GPIO_AD_B1_00(I2C1_SCLK) |
J23_6 |
|
PWDN |
P1 |
GPIO_AD_B1_02(GPIO1_IO18) |
J22_7 |
|
RESET |
P2 |
GPIO_AD_B1_03(GPIO1_IO19) |
J22_8 |
|
3.3V |
P18 |
3.3V |
J22_7 |
|
GND |
P17 |
GND |
J22_8 |
In order to reduce the impact of the signal, MIMXRT1050-EVKB removes R323, R316, R309, and D6 on the board.
The physical connection situation is as follows:
Fig 3
2.2 Software configuration
Since the flexIO of RT1050 is different from the 8 shifters of RT1010, the DMA configuration needs to be modified. The difference code of flexio_ov7670 is as follows:
static FLEXIO_CAMERA_Type s_FlexioCameraDevice = {
.flexioBase = BOARD_CAMERA_FLEXIO_INST,
.datPinStartIdx = BOARD_CAMERA_FLEXIO_DATA_PIN_START_INDEX,
.pclkPinIdx = BOARD_CAMERA_FLEXIO_PCLK_PIN_INDEX,
.hrefPinIdx = BOARD_CAMERA_FLEXIO_HREF_PIN_INDEX,
.shifterStartIdx = 0U,
.shifterCount = 4,
.timerIdx = 0U,
};
static void configDMA(void)
{
uint32_t soff, smod = 0u, size=0u;
while(1u << size < DMA_TRSF_SIZE) /* size = log2(DMA_TRSF_SIZE) */
{
size++;
}
if(DMA_TRSF_SIZE == DMA_MINOR_LOOP_SIZE)
{
soff = 0u;
}
else
{
soff = DMA_TRSF_SIZE;
while(1u << smod < DMA_MINOR_LOOP_SIZE) /* smod = log2(DMA_MINOR_LOOP_SIZE) */
{
smod++;
}
}
/* Configure DMA TCD */
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].SADDR = FLEXIO_CAMERA_GetRxBufferAddress(&s_FlexioCameraDevice);
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].SOFF = soff;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].ATTR = DMA_ATTR_SMOD(smod) |
DMA_ATTR_SSIZE(size) |
DMA_ATTR_DMOD(0u) |
DMA_ATTR_DSIZE(size);
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].NBYTES_MLNO = 16;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].SLAST = 0u;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].DADDR = (uint32_t)(*pFlexioCameraFrameBuffer);
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].DOFF = 8;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].CITER_ELINKNO = DMA_MAJOR_LOOP_SIZE;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].DLAST_SGA = -OV7670_FRAME_BYTES;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].CSR = 0u;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].CSR |= DMA_CSR_DREQ_MASK;
DMA0->TCD[FLEXIO_CAMERA_DMA_CHN].BITER_ELINKNO = DMA_MAJOR_LOOP_SIZE;
/* Configure DMA MUX Source */
DMAMUX->CHCFG[FLEXIO_CAMERA_DMA_CHN] = DMAMUX->CHCFG[FLEXIO_CAMERA_DMA_CHN] & (~DMAMUX_CHCFG_SOURCE_MASK) | DMAMUX_CHCFG_SOURCE(FLEXIO_CAMERA_DMA_MUX_SRC);
/* Enable DMA channel. */
DMAMUX->CHCFG[FLEXIO_CAMERA_DMA_CHN] |= DMAMUX_CHCFG_ENBL_MASK;
}
The code structure adopts: the camera uses flexIO mode to collect DMA transfer. After collecting one frame, DMA stores the data into the buffer, and then displays one frame of data uniformly on the LCD.
Since there are many configuration codes for flexIO OV7670 and LCD SPI, we will not explain them one by one here. Please check the attached code source code for details.
There is a header file of horsepic.h in the code. This file is a 320*240 RGB565 picture of a horse. It is used to test the LCD display separately. Usually after connecting the LCD, you need to test the LCD display separately. You can use a fixed picture to get the display. , here is the method of converting the picture into a C array: First adjust the picture to the LCD resolution size, and then convert it through the LVGL online conversion tool, select CF_RGB565A8, but the RGB565 generated by this format will have 1 more byte each, you can do it yourself After deletion, it can be called by code:
https://lvgl.io/tools/imageconverter
Display horse picture code:
convert8to16();
ILI9341_FillPic(0, 0, OV7670_FRAME_WIDTH-1u, OV7670_FRAME_HEIGHT-1u, (uint16_t *)(horse16));
Display result：
Fig 4
3 Test result and summarize
About RT1050-EVKB, use flexIO to collect OV7670 data and display the situation through TFT LCD. Please check the video for the specific code situation. Check the attached source code. You can see from the video results that the flexIO OV7670 camera data can be successfully displayed and the code can successfully run the function.
