GD32 58mm Thermal Micro Printer Solution

Single chip microcomputer STM32L151CCU6

KT2520K26000DCW28QAS import spot

Parallel thermistor / NTC thermistor / product complete / Sunlord first-class agent

NCP18XH103F03RB MURATA Murata thermistor original spot

Micro-printer is mainly a micro-printer with a width of less than 84mm, including POS printer (commercial POS, financial POS), tax-controlled printer, ATM, ECR, KIOSK and other built-in or external micro-printers. Micro-printers are widely used in various Industries, such as finance, retail, catering, lottery, transportation (including taxis, airline tickets, road and bridge tolls, etc.), gas stations, health care, postal services, utility meter reading, mobile police systems, mobile Government system and so on.

There are many types of micro-printers, which can be classified into pin-type micro-printers and thermal micro-printer thermal transfer micro-printers. The printing method of the needle type micro-playing method is that the printing needle impacts the ribbon, and the ink of the ribbon is printed on the paper. The heat-sensitive method is to discolor the heat-sensitive medium coated on the printing paper by heating, and the thermal transfer is The powder on the ribbon is printed on the printing paper by heating.

The thermal printer has the advantages of fast printing speed, low noise, little mechanical loss on the print head, no need for ribbon, and no trouble of replacing the ribbon, and has become the most popular printer in the market.

Gezhi Microcore Technology specializes in thermal printer control and offers a complete thermal printer solution.

Composition of the program

The micro thermal printer is mainly composed of a thermal print head and its peripheral circuits, a main controller (MCU) circuit, a power supply, a communication interface circuit and human-computer interaction.

Figure 1 Printer solution block diagram

Thermal printer hardware design

This solution uses the Fujitsu FTP-628 print head. The FTP-628 print head is mainly composed of stepper motor, heating plate, overheat detection, and paper out detection.

1. The MCU realizes paper feeding by controlling the stepping motor;

2. The MCU determines that the heating element is heated by the input data being l or 0, thereby generating a dot line to be printed on the thermal paper;

3. The MCU detects the thermistor value through the ADC to determine whether to activate the overheat protection;

4. The MCU determines if there is paper by detecting the out-of-paper optocoupler output.

Figure 2 Print head hardware peripheral design

Master control MCU

Figure 3 GD32 Series ARM Cortex-M3 MCU

MCU uses GD32 F103C8T6, GIGA DEVICE company based on ARM CORTEX M3 architecture 32-bit processor, the main parameters:

1) 72M system frequency

2) 64KB FLASH, 20KB SRAM

3) 2 SPI, 3 UART, 2 I2C

4) 3 32-bit timers

5) 2 10-channel 12-bit ADCs with a sampling frequency of 1M

6) Up to 37 GPIOs

7) Integrated USB DEVICE

8) Support DMA data transmission

9) Support for JTAG and SWD debugging

10) (10) 48-pin LQFP package

The MCU serial communication supports DMA mode for high-speed serial communication. The MCU does not need to enter the serial port interrupt service program frequently, and the MCU resources are less occupied. The SPI speed is up to 25M, so the font can use IO less SPI FLASH, but no speed. Concern; GPIO is fast, so use IO to achieve serial timing, send data to the print head, the speed is very fast; internal ADC can be used for print head temperature detection; 20K SRAM, even if the graphic printing method needs to be compared Big data buffering, no need to expand SRAM; integrated USB DEVICE, communication with PC, simple and fast.

Figure 4 Thermal printer main control board

software design

The program software is divided into the following major modules

1. Communication processing, including UART, parallel port, USB three communication methods.

2. Font SPI FLASH driver for reading font data from SPI FLASH

3. Print head drive control, including data sent to the print head and stored data, stepper motor control, print head temperature detection, and paper out detection.

4. Print instruction processing