Using the HT9B95G in Three-Phase Electric Meter LCD Display Panel Applications

Transcription

1 Using the HT9B9G in Three-Phase Electric Meter LCD Display Panel Applications D/ A09E Introduction The HT9B9G is an LCD driver device which includes a display RAM mapping function and has multiple display modes, namely SEG COM or 9SEG 8COM. This application shows how the HT66F0 microcontroller, when used as a host MCU, can transfer data from a three phase electric meter driven by the HT9B9G, and how to display multiple images. The purpose of the application is to allow users to grasp the characteristics and applications of the HT9B9G more clearly. Operation Principles HT9B9G Basic Features Operating Voltage.V~.V Integrated oscillator circuitry to provide timing for internal control and driving signals Four Selectable frame frequencies 80/7/6/0Hz External VLCD pin to supply LCD operating voltage Integrated LCD driving voltage adjustment function Internal LCD bias generation with voltage-follower buffers Power Save Mode for low power I C-bus serial interface Internal 9 8 bits RAM for display data storage Duty /, bias / or duty / 8, bias / Display patterns / duty-up to patterns or /8 duty- up to 9 8 patterns Package Type COG (Chip On Glass) / A09E

2 HT9B9G LCD Display RAM The SEG and COM control the LCD control the on state of the corresponding LCD segment. A logic 0 in the RAM bit-map indicates an off state. The HT9B9G can select either a 9SEG 8COM or SEG COM driving mode. The LCD RAM map is implemented as shown in the following table. Address COM0 COM COM COM COM COM COM6 COM7 Output 00H 0H H 6H RAM Data Bit 7 Bit 6 Bit Bit Bit Bit Bit Bit 0 Table. 9SEG 8COM LCD Display RAM SEG0 SEG SEG7 SEG8 Address COM0 COM COM COM Output COM0 COM COM COM Output 00H SEG0 SEG 0H SEG SEG H SEG8 SEG9 H SEG0 SEG H SEG RAM Data Bit 7 Bit 6 Bit Bit Bit Bit Bit Bit 0 Table. SEG COM LCD Display RAM When the host MCU updates the HT9B9G display RAM data using the I C interface the MSB of the I C data is D7 as the following table shows. HT9B9G Data Communication The HT9B9G includes an I C serial interface. Both commands and display RAM data is transferred on this bus following the I C protocol. This two line interface includes a serial data line with the name SDA, and a serial clock line with the name SCL. As devices connected to the bus have open-drain outputs the SCL and SDA lines are connected to the positive supply via pull-up resistors with a typical value of.7kω. The HT9B9G I C Clock can have a frequency up to 00kHz. Both SCL and SDA lines have an internal RC filter to improve the anti-interference ability. With regard to the HT9B9G I C R/W operation and the related command set, refer to the HT9B9G datasheet. / A09E

3 HT9B9G LCD Driving Voltage Adjustment The LCD driving voltage is provided by the external pin VLCD. This V LCD voltage can output the maximum LCD driving voltage V0 after being adjusted by the internal voltage adjustment circuit. V0 can be set to a value between V LCD and 0.9 V LCD using the LCD driving voltage adjustment command however the condition V LCD-V0 > 0.6V must be met. If the V LCD-V0 voltage is equal to or less than 0.6V, the output voltage will be unstable. V0 passes through an internal bias voltage generator. When the bias is /, the voltage V OP (V0 V SS) is divided into four voltage levels using internal resistors. These voltages are V SS, /V OP, /V OP and V OP; when the bias is /. V OP is divided into five voltage levels which are V SS, /V OP, /V OP, /V OP and V OP. These voltages together with the driving timing will generate the LCD driving signals. HT9B9G Power On Initialisation All the Commons and Segments output VSS The LCD bias generator and the system oscillator are off Display RAM address is 00H Frame frequency is 80Hz Power save mode is ormal Current LCD driving output wave is B type inversion LCD display is off Driving mode is /8 duty and / bias ote that, when the device is powered on, it requires at least ms for the IC internal reset to be effective for proper initialisation, after this time has elapsed I C data transfer can begin. / A09E

4 Demo H/W Block Diagram System Block Diagram VSS VLCD SDA SCL Top Board HT9B9G(COG) Three Phase Meter LCM(8COM 6SEG) DC-DC Boost Circuit (HT799) 00 Li+ Battery VSS VLCD SDA SCL HT66F0 (8SOP) AC-DC Converter (FAS--W) Li+ Battery Charger (APL0) AC00V~0V P IC Micro USB DC V Bottom Board Fig System Block Diagram The complete Demo board consists of both a Top Board and a Bottom Board as shown in Figure. The data transfer between the two parts is completed by I C communication. Top Board LCM (HT9B9G) -Drive Condition /8 duty & / bias; Operating Voltage.0 V; LCD operating voltage is provided by the external VLCD pin. Bottom Board Power Supply Circuit Provides three power supply modes AC power (00~0V AC), power adapter (DCV, Micro USB interface) and lithium battery (00/a battery) DC-DC boost circuit when only powered by the Lithium battery, enable DC-DC boost IC (HT799), boost the battery voltage to V to power the host MCU and HT9B9G. Lithium battery charging circuit when powered by the AC power or the external power adapter, enable the Lithium battery charging management IC (APL0) to charge the Lithium battery. Host MCU The host MCU of this Demo is HT66F0 which can transfer data with the HT9B9G to implement many kinds of images. The ICP interface is used to download the code. / A09E

5 Application Circuit The application circuit consists of both a Top Board and a Bottom Board as shown in Figure and Figure. P TOP_SDA TOP_SCL TOP_VLCD TOP_ TOP_VLCD TOP_ C0 0 C 0 TOP_VLCD TOP_ TOP_SDA TOP_SCL C R R6 C C8 C9 LCM Figure Top Board Circuit F A fuse J AC DIP SOCKET U FG Z ZR C 0.uF/7VAC L V+ V- C D C 70uF/V 0.uF TVS/SMAJ6.0CA R K R 0K D D SS SS IO_ACI IO_USBI C C 0nF 0nF R K D9 R 0K TVS/MSMP6.0A R7 R6 R MICRO USB C6 uf/0v/06 VLCD MCU_ FAS--W VBAT R 0K C0 Roc 8K uf/0v/06 C7 uf/0v/06 C8 0.uF L.uH/CD 6 OC LX VI GD E FB U HT799-SOT-6 D SS R 0K/% C9 R.9K/% uf/0v/06 D SS C0 uf/0v/06 D6 SS VBAT R IO_BOOST_DISABLE R0 R 0K Q AO00 R7 K D7 LED U IO_CHG_DET STAT ISET VBAT GD BATT VI S APL0-SOT- C R J.7uF 00K AD_BATV R6 Li+ BAT/00 Single Battery Box C 00K nf R8 K R0 Q AO00 R9 0K IO_BAT_CHGE MCU_ U ADC_VREF VI VOUT C 0.uF GD HT7----SOT89 C 0uF J R VSS VLCD MCU_ RST ICPCK ICPDA J SDA SCL D8 MCU_ 8 C6 C C 0.uF ICPDA MCU_ R 6 00K 7 R 0 RST 8 IO_CHG_DET 9 0 R C7 0.uF RESET_KE PA0/C0X/TP0_0/A0 VSS/AVSS PB/XT PB/XT PB/OSC PB/OSC PB0/RES PC/TPB_/SCOM PC0/TPB_0/SCOM0 PC7/[TPA]/SCOM PC6/[TP0_0]/SCOM PD/[TCK]/TP_0/[SDO] PD/[TCK0]/[SDI/SDA] U 8 PA/TPA/A 7 PA/TCK0/C0+/A 6 PA/IT0/C0-/A PA/IT/TCK/A PA/CX/SDO/A PA6/SDI/SDA/A6 PA7/SCK/SCL/A7 PB/SCS/VREF 0 PC/TCK/PCK/C+ 9 PC/PIT/TP_0/C- 8 PC/[IT0]/[PIT]/TCK/TP_ 7 PC/[IT]/TP0_/TPB_/[PCK] 6 PD0/[TCK]/TP_/[SCS] PD/[TP_0]/[SDO]/[SCK/SCL] HT66F0-8SOP-A IO_BAT_CHGE ICPCK AD_BATV IO_ACI IO_USBI ADC_VREF IO_BOOST_DISABLE R SDA R6 SCL C8 0.uF MCU_ R R.7K.7K SDA SCL Figure Bottom Board Circuit In the Top Board circuit, C, C, C8 and C9 are reserved components, they are not soldered in the Demo. / A09E

6 Power Supply Circuit F A fuse J AC DIP SOCKET U FG Z ZR C 0.uF/7VAC L V+ V- C D C 70uF/V 0.uF TVS/SMAJ6.0CA R K R 0K D D SS SS IO_ACI IO_USBI C C 0nF 0nF R K R 0K D9 TVS/MSMP6.0A R7 R6 R MICRO USB C6 uf/0v/06 VLCD MCU_ FAS--W Figure AC Power and Power Adapter (Micro USB) Power Supply Circuit VBAT S AD_BATV C nf R 00K R6 00K J Li+ BAT/00 Single Battery Box Figure 00 Lithium Battery Power Supply Circuit The Demo provides three power supply modes. AC Power Supply Mode AC power (00~0V AC) passes first through a 0V/A fuse and then passes through a D7K voltage dependent resistor and 0.μF capacitor (safty). The V/A DC power supply is output by the AC-DC power conversion module.. Power Adapter Power Supply Mode Use an external DCV/A power adapter as the power supply provided on the Micro USB interface.. Lithium Battery Power Supply Mode The Demo provides a 00 lithium battery holder. When the power supply button S is on a 00 lithium battery can be used as the power supply. As the host MCU and the HT9B9G both use a.0v supply, when it is lithium battery powered, a DC-DC boost converter is required to boost the voltage to.0v. The above three kinds of power supply are connected with a Schottky diode SS. The IO_ACI and IO_USBI are used to detect the AC power and the external power adapter. When the MCU detects that either AC power or a power adapter is connected then the battery boost circuit should be switched off. 6 / A09E

7 DC-DC Boost Circuit VBAT R 0K C0 Roc 8K uf/0v/06 C7 uf/0v/06 C8 0.uF 6 L.uH/CD OC LX VI GD E FB U HT799-SOT-6 D SS R 0K/% R.9K/% C9 uf/0v/06 D SS C0 uf/0v/06 D6 SS VBAT IO_BOOST_DISABLE R0 R 0K Q AO00 Fig.6 DC-DC Boost Circuit When the AC power and the external power adapter are not connected, the Demo uses a lithium battery. When the lithium battery voltage is higher than.v, the host MCU pin IO_BOOST_DISABLE outputs a low level voltage to enable the DC-DC boost IC HT799 to increase the voltage to V to provide a A output current. The boost IC output voltage can be adjusted by changing the R and R resistor values. Lithium Battery Charging Circuit J IO_CHG_DET R7 K U STAT GD BATT ISET VI APL0-SOT- Li+ BAT/00 Single Battery Box D7 LED C.7uF R8 K Q AO00 R0 R9 0K IO_BAT_CHGE Fig.7 Lithium battery charging circuit When AC power or an external power adapter is detected by the MCU, the IO_BAT_CHGE pin outputs a high level to enable the lithium battery charging IC APL0 to charge the 00 lithium battery. The APL0 used by the Demo is an APEC product with an SOT- package type. Its input voltage is.v~6.v and charging current is 0.A~0.A which can be adjusted by changing the R8 resistor value. The battery will stop charging when its voltage rises to.v and it will start to charge again when the battery voltage falls to.0v. The resistance of the Demo R8 is K and the charging current is about 00mA. When the D7 LED is on, this indicates that the lithium battery is being charged. When fully charged the LED will be switched off automatically. 7 / A09E

8 MCU Control Circuit J MCU_ MCU_ RST ICPCK C6 C D8 ICPDA C 0.uF 8 J R VSS VLCD SDA SCL ICPDA MCU_ R 6 00K 7 R 0 RST 8 IO_CHG_DET 9 0 R C7 0.uF RESET_KE PA0/C0X/TP0_0/A0 VSS/AVSS PB/XT PB/XT PB/OSC PB/OSC PB0/RES PC/TPB_/SCOM PC0/TPB_0/SCOM0 PC7/[TPA]/SCOM PC6/[TP0_0]/SCOM PD/[TCK]/TP_0/[SDO] PD/[TCK0]/[SDI/SDA] U 8 PA/TPA/A 7 PA/TCK0/C0+/A 6 PA/IT0/C0-/A PA/IT/TCK/A PA/CX/SDO/A PA6/SDI/SDA/A6 PA7/SCK/SCL/A7 PB/SCS/VREF 0 PC/TCK/PCK/C+ 9 PC/PIT/TP_0/C- 8 PC/[IT0]/[PIT]/TCK/TP_ 7 PC/[IT]/TP0_/TPB_/[PCK] 6 PD0/[TCK]/TP_/[SCS] PD/[TP_0]/[SDO]/[SCK/SCL] HT66F0-8SOP-A IO_BAT_CHGE ICPCK AD_BATV MCU_ U ADC_VREF IO_ACI IO_USBI ADC_VREF MCU_ VI VOUT IO_BOOST_DISABLE R R SDA.7K R6 SCL C8 0.uF SDA SCL R.7K C 0.uF GD HT7----SOT89 C 0uF Fig. 8 MCU Control Circuit Figure 8 shows the MCU control circuit with I/O pins PC and PC used to generate the I C host signals to exchange data with the HT9B9G in the LCM to implement the screen display. At the same time, the HT66F0 will detect the AC power and the power adapter using pins PA and PA. If there is a connection, the lithium battery voltage will be sampled by the A/D to control the APL0 to determine whether to charge the lithium battery. If a lithium battery power supply is used, the battery voltage will also be sampled by the A/D to determine if the boost function should be enabled. The HT66F0 includes a -bit SAR ADC with the ADC reference voltage provided by a HT7 regulator giving a.v output. J in the figure 8 provides the power supply for the HT9B9G and the I C interface. J is the programming interface of the HT66F0. The HT66F0 I/O control functions are as follows MCU Pin Corresponding etwork Label Control Function 9 IO_CHG_DET APL0 charging state detection 9 SCL I C Interface Serial Clock 0 SDA I C Interface Serial Data IO_BOOST_DISABLE DC-DC boost enable control IO_USBI External power adapter connection detection IO_ACI AC power connection detection 6 AD_BATV Lithium battery voltage detection 8 IO_BAT_CHGE Lithium battery charging enable control Display Circuit P TOP_SDA TOP_SCL TOP_VLCD TOP_ TOP_VLCD TOP_ C0 0 C 0 TOP_VLCD TOP_ TOP_SDA TOP_SCL C R R6 C C8 C9 LCM Fig. 9 Display Circuit Figure 9 shows the display circuit. The HT9B9G (COG) is in the LCD Panel and connects the Segment and Common with the LCD Panel and provides pins for external connection, VSS, VLCD,, SDA and SCL. 8 / A09E

9 S/W Flowchart The HT9B9G Demo Board programs are written in C language, including the main program, Lithium battery charging and boost control subprogram, display subprogram, update HT9B9G display RAM subprogram, timer interrupt subprogram etc. The following content gives details about the program description. Main Program Flowchart Power on MCU system initial GCC_CLRWDT() Fun_Battery_Check() Lithium battery charging function and the boost function on/off check bpower_steady=? System power-on delay for 00ms Complete HT9B9G initialization; brefresh_time_ms=0; bht9b9g_initial=0 ; brefresh_time_xxs=; bht9b9g_initial=0? HT9B9G Initialization Is Completed? brefresh_time_xxs=? Update display screen? binc_kwh_ig=? Dynamic display of meter Billing? brefresh_time_xxs=0; bupdate_lcd_disp=; brefresh_kwh_0ms=? Update electricity? Fun_DISP_STEP() Update Display data to RAM buffer (if switch the display Step, then set brefresh_time_xxs=; bupdate_lcd_disp=0;) Fun_Inc_Kwh_xx()update the current electricity brefresh_kwh_0ms=0; brefresh_time_xxs=; bupdate_lcd_disp=0; bupdate_lcd_disp=? Update HT9B9G DISP RAM? Fun_Update_LCD_DISP() Update RAM Buffer Data to HT9B9G and check the state of brefresh_time_ms brefresh_time_ms= then quit the current update brefresh_time_ms=0; Fig. 0 Main Program Flowchart 9 / A09E

10 When the Demo Board powered on the HT66F0 executes the following system initialisation operations first MCU_IITIAL(); //set WDT, Comparator, IO state, TB0 timer interrupt, AD functions, etc. RAM_CLR(); //clear MCU RAM In the main loop the MCU detects the power supply mode first, then waits for 00ms until the system is stable to allow the HT9B9G to have enough time to complete the IC internal power on reset action. After the system is stable, then according to the power supply mode and the lithium battery voltage, it can be decided whether to turn on the lithium battery boost circuit and the charging circuit. Then using two ordinary I/Os to simulate the I C host signals, the data transmission between the MCU host and the HT9B9G (slave) in the LCM can be implemented. Communication between the MCU and the HT9B9G Buffer space is assigned to store the LCD display data in MCU. When updating the images, firstly update the data to the RAM buffer and then write the data of the RAM buffer into the HT9B9G via the I C interface. The flag description of the main process in the Demo Code is as follows Flag bpower_steady bht9b9g_initial brefresh_time_xxs binc_kwh_ig brefresh_kwh_0ms bupdate_lcd_disp brefresh_time_ms Function bpower_steady=,indicates that the system power on delay is finished and the delay time is 00ms bht9b9g_initial=,indicate the HT9B9G Initialisation operation Calculate the static display screen and stage persistence time, when brefresh_time_xxs=, display the next image binc_kwh_ig=, Enter the meter billing dynamic display Calculate the time of a dynamic screen update, when brefresh_kwh_0ms=, the battery indicator value is updated bupdate_lcd_disp= update the data to the HT9B9G Display RAM When writing data to the HT9B9G, if brefresh_time_ms =, then stop writing data. When the HT9B9G initialisation is finished, start to write the data from the next address. DEMO CODE Main Flow Description. The MCU will update the display contents when brefresh_time_xxs= or (binc_kwh_ig= & brefresh_kwh_0ms=), When one of these two conditions is satisfied, the system will update the display data to the MCU RAM Buffer which stores the LCD display data and then set bupdate_lcd_disp= to update the data in the MCU RAM Buffer to the HT9B9G Display RAM.. When bupdate_lcd_disp=, the MCU will update the data in the MCU RAM Buffer to the HT9B9G. At the same time, detect the brefresh_time_ms state, the system will update the data to the HT9B9G in many continual ms time fragments to complete the screen update. The purpose is to give consideration to the HT9B9G initialisation and improve the ESD & EFT capability. For the moment the HT9B9G initialisation is only executed when the system is powered on for this Demo. 0 / A09E

11 HT9B9G Initialisation Flowchart Power on Software Reset Setting Duty and Bias Setting LCD Driving Voltage Adjustment LCD Current Mode Setting LCD Frame Frequency Setting LCD Output Waveform Setting ext processing Fig. HT9B9G Initialisation Flowchart Before the LCD displays data the HT9B9G should be initialised. After the initialisation, the HT9B9G display RAM can be written to and the image display can be implemented. HT9B9G Initialisation and setup a. Software Reset Setting (o operation) b. Duty and Bias Setting (/8duty, /bias) c. LCD Driving Voltage Adjustment (V0=.000V) d. LCD Current Mode Setting (ormal current) e. LCD Frame Frequency Setting (Frame Frequency=80Hz) f. LCD Output Waveform Setting (B type inversion) g. System oscillator and Display on/off setting, LCD Display on, internal system clock on) / A09E

12 Display Subprogram Flowchart start Step0 Power on initialisation? After booting, the screen lights up for seconds, flashes times and enters the next stage. Step Early stage electricity tips?.show the last month's electricity consumption and electricity bill.show the last two months' electricity consumption and electricity bill Step Simulate electric meter billing at stage? Simulate electric meter billing, at stage, date Simulate the meter billing of flat, peak, sharp and bottom times.show the unit price of flat, peak, sharp and bottom times.the current electricity of flat, peak, sharp and bottom times and the total electricity Step Simulate electric meter billing at stage? Simulate electric meter billing, at stage, date 0-0-.Simulate the meter billing of flat, peak, sharp and bottom times.show the unit price of flat, peak, sharp and bottom times.the current electricity of flat, peak, sharp and bottom times and the total electricity Step Simulate electric meter billing, at stage? Simulate electric meter billing, at stage, date 0-0-.Simulate the meter billing of flat, peak, sharp and bottom times.show the unit price of flat, peak, sharp and bottom times.the current electricity of flat, peak, sharp and bottom times and the total electricity Step Simulate electric meter billing, at stage? Simulate electric meter billing, at stage, date Simulate the meter billing of flat, peak, sharp and bottom times.show the unit price of flat, peak, sharp and bottom times.the current electricity of flat, peak, sharp and bottom times and the total electricity consumption Step6 Monthly electricity price statistics query?.the electricity consumption and electricity bills in four stages of the current month.the electricity consumption and electricity bills in four times of the current month.the electricity consumption of the current month and the maximum requirements Step7 Pressure loss inquiry?.pressure loss times and cumulative time inquiry.pressure loss start date and time.pressure loss start end date and time Step8 Voltage current and power inquiry?.a phase voltage current and power inquiry.b phase voltage current and power inquiry.c phase voltage current and power inquiry Step9 Other function?.surplus electricity inquiry.recharge electricity bill.communication mode and address inquiry, etc..return to Step0 Return Fig. Display Subprogram Flowchart The display subprogram is used to process the contents of the LCM display update. When the update screen displays the contents, the system will update the data to the MCU RAM buffer which stores the LCD display data. The whole process of the simulation of a three-phase electric meter is divided into 0 processes. They are Initialisation after power on, previous period reminder, simulate electric meter billing, condition inquiry, etc. After power on and initialisation, the LCM will start to display from the initialisation and then each process is displayed automatically until the 0 processes are all completed, after which the cycle begins again. / A09E

13 Lithium Battery Charging and Boost Control Subprogram Flowchart Start AC power or power adapter is connected? bpower_steady=? Loop 00mS to wait for the system power on stability bpower_steady= Powered by lithium battery bboost_check=? Disable DC-DC boost function Disable lithium battery charging function bcharge_check=?. Enable lithium battery charging, for S. Disable lithium battery charging, for S. bcharge_check= lithium battery voltage is higher than.v? lithium battery voltage is higher than V? Disable lithium battery charging function Enable DC-DC boost function bpower_steady= Enable lithium battery charging function Disable DC-DC boost function bpower_steady=0 Loop 00mS to wait for the system power on stability bboost_check= Return Fig. Lithium Battery Charging and Boost Control Subprogram Flowchart The MCU checks the AC power and the external V DC power adapter to see whether it is connected to IO_ACI and IO_USBI. If the AC power and the power adapter are not detected the power supply of the Demo is supplied by a Lithium battery. If the AC power or the power adapter is detected first, then turn on the Lithium battery charging function for S and then close the function for S. Finally, according to the A/D sampling of the lithium battery voltage, decide whether to enable the lithium battery charging function. When the battery box has a 00 lithium battery and the voltage is higher than V, the lithium battery charging function is enabled, otherwise it is disabled. If using the lithium battery power supply disable the lithium battery charge function. The A/D function will sample the current lithium battery voltage. If the voltage is higher than.v, then enable the DC-DC boost function and if the voltage is less than.v, it shows that the battery is low so disable the DC-DC boost function. / A09E

14 Program Example The program Configuration Option is as follows, refer to the attachments for the program. ;=================================================================== ;SysVolt.0V ;SysFreq HIRC 8MHz ;WDT Disable ;WDT clock source fs fsub ;I/O or Reset function RESB ;SIM FunctionDisable ;LVR FunctionEnable ;LVR Voltage Selection.V ==================================================================== Conclusions This application used the HT66F0 as the master MCU to control a three phase electric meter LCM display and also introduced the HT9B9G features and related operations. The application gave some advice for programming so that users will have a better understanding of how to master HT9B9G applications. / A09E