Application of the hottest ultra-thin display OLED

Application of ultra-thin OLED display in gyro theodolite

Abstract: Based on a brief introduction of CMOS oled/pled display driver ssd1303 chip produced by Solomon company, this paper focuses on the application of ultra-thin OLED display p09703 embedded with ssd1303 driver chip, the latest product of Taiwan Renbao company, in gyro theodolite, and gives the hardware circuit diagram and software flow chart, It provides a reference for the development of portable devices with display screens

key words: OLED ssd1303 arm gyroscope

gyro theodolite is a precision instrument that measures the true north direction of the instrument erection point by sensing the horizontal component of the earth's rotation, so that we can choose the right product according to your actual situation. The working condition of your product is similar to that of an electronic theodolite, but the difference is that the electronic theodolite can only measure the relative included angle of two targets, while the gyro theodolite can not only measure the relative included angle between targets, And the included angle between the target and the geographical North or true north direction can be measured. The installation of the instrument is not level. There are two places where the installation may be not level. The usually used roll pressure recording paper is carried out in the field, and the environmental conditions are relatively poor. In the past, the display part was realized by liquid crystal, which brought about the problem that in addition to weight and volume, low temperature was realized by heating, and the power consumption was large. Field operations had high requirements for batteries. Another problem is that no measures can be taken to solve the problem of unclear liquid crystal display under the sun, which is determined by the characteristics of liquid crystal display itself

oled has many attractive features in displaying information. OLED has no viewing angle problem of LCD, and can provide full viewing angle display. Because OLED has the characteristics of self illumination, its brightness is much higher than LCD, and it does not need backlight like LCD, so it not only improves the effective power of the power supply, but also consumes only half of the power of LCD, and the thickness of the device is thinner than LCD. OLED response time is 1000 times faster than a typical LCD. Therefore, it has the advantages of high efficiency, high contrast, wide viewing angle and low working voltage [1 -2]. The ultra-thin OLED display p09703 produced by Taiwan re Bao company with embedded ssd1303 driver chip has 128X64 lattice numbers, a thickness of only 2.05mm, a weight of only 11.1g, and an operating temperature of -40 ℃ to +85 ℃. Using this product on the gyro theodolite solves the display problem very well. The following focuses on the implementation of circuit design

1 ssd1303 introduction

at present, several companies such as Solomon and Clare of the United States produce OLED drive IC. The ssd1303 that Solomon put into the market is an OLED driver chip that integrates row drive, column drive and controller. This drive is 132 × It is designed for 64 dot matrix OLED graphic display, including row driver, column driver, current reference generator, contrast control, oscillator and several MCU interface modes. The working logic voltage is 2.4V ~ 3.5V, with rich software functions. It supports four color choices and 64 level control of each color. Its software contrast has 256 level control and 132 embedded × 64 bit graphic dynamic random access memory (gddram) provides row remapping, column remapping, vertical scrolling and partial display functions. The driver is suitable for a variety of OLED displays with different pixel sizes and colors

2 hardware connection between p09703 and LPC2131

lpc2100/llpc2105/lpc2106 series microcontroller is a microcontroller launched by Philips semiconductor based on 16/32-bit arm7tdmi-s CPU with 128/256 Kbytes (KB) embedded high-speed flash memory. 128 bit wide memory interface and unique acceleration structure enable 32-bit code to run at the maximum clock rate. Applications that strictly control the code size can use 16 bit thumb mode to reduce the code size by more than 30%, while the performance loss is very small. Because the lpc2100/llpc2105/lpc2106 series microcontrollers use a very small 64 pin package, extremely low power consumption, multiple 32-bit timers, 4-way 10 bit ADC PWM output and up to 9 external interrupts, they are particularly suitable for industrial control, medical systems, access control, electronic cash registers (POS) and other application fields. Because LPC2100 series microcontrollers do not have external bus controllers, it is not very convenient for them to connect external expansion chips. However, because of their fast speed, even if the software analog bus external expansion chip is used, it is much faster than the ordinary 80C51, and the rich on-chip resources are not comparable to the ordinary 51

since p09703 and p09702 have the same graphic display controller ssd1303, and the hardware interface of p09702 is suitable for test connection, the following takes p09702 and LPC2131 as an example to explain. Because the logic level of OLED display p09702 is 2.4V - 3.5V, we choose the microcontroller LPC2131 based on arm7tdmi-s and single power supply produced by Philips company as the controller. Figure 1 shows the power supply, clock In addition to the minimum circuit for the normal operation of an embedded processing system such as reset, the power circuit provides analog 3.3V and digital 3.3V to improve the working stability of the system. At the same time, the hard UTM experimental machine of p09702 and LPC2131 is drawn, including the connection mode of one or more vertical bearing column parts

application of ultra-thin display OLED in gyro theodolite

3 software programming

in connection with computer, the interface of ssd1303, including data input buffer, data output latch, instruction register and decoder, busy state trigger and timing control circuit, has high-performance interface control circuit. The computer can access ssd1303 at any time without judging its current state. Unlike the T6963C controller previously used, ssd1303 judging the busy state is not so important in operation, because the interface unit of ssd1303 can receive computer access in time. Only when the computer transmits a large amount of data to the display memory, it conflicts with the transmission of display data from the control unit to the driving unit, and a "snowflake" will appear on the display screen. However, due to the short gap time and the visual inertia of the human eye, the "snowflake" phenomenon cannot be seen. Sometimes when the busy flag is judged and then displayed for data transmission, the busy flag has disappeared. Because of these, the operation process of computer accessing ssd1303 is very simple. However, it should be noted that there are several sets of sequential circuits in the interface control circuit of ssd1303 to meet the requirements of different computer operation sequences. The setting end of the timing adaptation circuit is bs0, BS1, BS2. Select different connections between BS1 and BS2 in p09703 to determine whether to select intel8080 timing or M6800 timing. In p09702, since BS1 and BS2 are not selected, intel8080 timing has been set at the factory, so the following procedure is intel8080 timing

#define AD0_ PIN_ Num8//8-bit data bus

define DC_ PIN_ Num 5//p0.5 data/command control bit, low level - command operation, high level - data operation

define wr_ PIN_ Num 6//p0.6 write data/command control bit, write

define Rd when high level changes to low level_ PIN_ Num 7//p0.7 read data/command control bit, effective at low level

define CS_ PIN_ Num 16//p0.16 enable bit, Low level valid

void exbusinit (void)//initialize p09702oled display bus

{uint32 temp;

//set pin connection module: dc_pin_num, wrpin_num, rdpin_num, cspin_num, ad0pin_num is GPIO

pinsel0 & = ~ (3> ad0u pin_num;

return (uint 8) temp;

}

void writecommand (uint8 data)//write the command code to p09702oled display

{ioclr = 1