JPH04166887A - Lcd display two-port memory circuit - Google Patents

Abstract

PURPOSE:To obtain resolution of over 1,000 beams in the vertical direction without response delay of a system in a memory circuit having an access port from a CPU and a LCD display port by rotating output data from the LCD display port by 90 degrees. CONSTITUTION:A CPU address is converted by an address converter 4, a LCD display address converter 5 so that output from a serial port 3 conforms to the scanning direction of a LCD display device rotated by 90 degrees, and an access unit from a CPU becomes 8 bits or 16 bits in the horizontal direction as before, and then connected to a multiport RAM 1. Thus, access from the CPU becomes possible without being conscious that a LCD is rotated by 90 degrees, and display data conforming to the LCD scanning direction can be obtained in relation to LCD display access. As a result, LCD display having high resolution can be obtained without response delay of the system.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an LC whose display screen is composed of two sets of LCDs.
The present invention relates to a two-port memory circuit for LCD display that enables LCD display with a vertical resolution of 1000 lines or more by using a D display device rotated by 90 degrees.

(Prior art) Currently, the duty ratio of LCD is 1/400 to 11
The limit is about 500. Therefore, a high-resolution LCD display device is realized by dividing the display screen into upper and lower halves and using two sets of LCDs 10I and 102, as shown in Figure 9.
CD display devices have been put into practical use.

Further, configuring one display screen using three or more sets of LCDs has not been put to practical use because it is difficult to physically arrange the LCD drivers (segment drivers).

In order to realize an LCD display with a vertical resolution of 1000 lines or more, the LCD display device must be rotated 90 degrees. Normally, the scanning direction of an LCD display device is the horizontal direction, so the CPU accesses the LCD display memory in the horizontal direction in terms of words or bytes, as shown in FIG. When the LCD is rotated 90 degrees, if the display memory is configured to match the scanning direction of the LCD display device, accesses from the CPU will be in the vertical direction as shown in FIG.

(Problems to be Solved by the Invention) However, in the conventional configuration described above, in order to use conventional image data and character fonts while access from the CPU remains in the vertical direction, it is necessary to convert the data using software. When data is converted using software, the system response becomes slow and the software itself becomes complicated.

The present invention solves the above-mentioned conventional problems, and aims to provide a two-board memory circuit for LCD display in which system response is not delayed and software is not complicated.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a memory circuit having an access port from the CPU and an LCD display port, in which access from the CPU remains the same as before.
The output data from the LCD display port is rotated by 90 degrees.

(Function) Therefore, by doing this, the CPU can access the LC.
You can now access it as before without being aware that D has been rotated 90 degrees, and when accessing the LCD display, you can obtain display data that matches the LCD scanning direction, and you can use the existing software as is. LCD display with a resolution of 1000 lines or more in the vertical direction is possible without slowing down the response of the system.

(Embodiment) FIG. 1 shows the configuration of a two-port memory device for LCD display in one embodiment of the present invention.

In FIG. 1, 1 is a multiport RAM, C
It has a random port 2 for access from the PU and a serial port 3 for access for LCD display. 4 is an address converter that converts the address from the CPU, 5 is L
Address converter for converting CD display addresses, 6
is an address selector that selects either address converter 4 or 5; 7 is a data converter; 8 is a data selector; 9 is a shift register; The address converter 4 from the CPU matches the scanning direction (vertical direction) and the access unit from the CPU is the same as before (8 bits or 16 bits in the horizontal direction).
, converted by the LCD display address converter 5 and connected to the multiport RAMI. The data signal on the CPU side is connected to the random port 2 of the multiport RAM 1 via the data converter 7, and for LCD display access, the output data from the serial port 3 of the multiport RAM 1 is input to the data selector 8, and the data is displayed on the LCD. The configuration is such that the selected address is selected and outputted via the shift register 9.

Next, the operation of the above embodiment will be explained. The following explanation is an example in which the data width from the CPU is 16 bits and the LCD display memory is 1024 x 2048 bits. The memory for LCD display is 256kb as shown in Figure 2.
It uses eight multi-port RAMs (64k x 4 configuration). As shown in Figure 3, the LCD display device consists of two sets of upper and lower LCDs arranged to form one screen, and is rotated 90 degrees to the left for use. 4 multiport RA
Assign M.

A and B assigned to the (left) part of Figure 3.

The C and D multiport RAMs are L as shown in Figure 4.
Assign the CD display screen. This can be done by converting or selecting data bits at address 0.7 on the CPU side, and at addresses 0.11 and 12.13 on the LCD display access, respectively.

The address signal from the CPU is sent to the multi-port R of A and B.
As shown in Figure 5, AM uses C2D multiport RAM.
As shown in FIG. 6, the address is assigned to a column address and a row address. Also, the LCD display address is the 7th address.
Assign as shown. By assigning addresses in this way, the bits of the multiport memory and the LC
The dots in the D display memory correspond as shown in FIG. As shown in Figure 8, the bits in the column direction of the multi-port memory match the scanning direction of the LCD display, and the LCD display data can be obtained by selecting data from the serial port with the selector. . Also, C.P.
For U-based access, 16-bit access can be performed in the conventional access unit with one read/write operation, and a system using an LCD with high resolution in the vertical direction can be configured without slowing down the system response. be able to.

(Effects of the Invention) As is clear from the above embodiments, the present invention enables the CPU to access the LCD as usual without being aware that the LCD has been rotated by 90 degrees. Display data that matches the scanning direction can be obtained, and an LCD display with high resolution (more than 1000 lines in the vertical direction) can be performed using conventional software without delaying system response.

[Brief explanation of drawings]

FIG. 1 shows the L CD' display 2 in one embodiment of the present invention.
A block diagram of a port memory device, FIG. 2 is a conceptual diagram of a multi-board RAM in an embodiment of the present invention, and FIGS. 3 and 4 are allocations of the multi-board RAM to an LCD display screen in an embodiment of the present invention. 5, 6, and 7 are address converter diagrams in one embodiment of the present invention, and FIG. 8 is a multiport RA diagram in one embodiment of the present invention.
A correspondence diagram between the address of M and the LCD display screen, FIG. 9 is a schematic diagram of a conventional LCD display device, and FIG. 10 is a diagram of a conventional LCD
Display Device Scanning Direction Diagram FIG. 11 is a scanning direction diagram when a conventional LCD is rotated 90 degrees to the left. l ・Multi-boat RAM, 2 ・・Random boat, 3 ・・Serial boat, 4.5 ・・Address converter, 6 ・・Address selector, 7
... data converter, 8 ... data selector, 9 ... shift register, 101.102
・・LCD. Patent applicant: Matsushita Electric Industrial Co., Ltd., \゛1 Agent: Tsune Hoshino 4-), -)- Figure 5 CPU address - Address Column address Figure 6 CPU address Row address Column address Figure 9

Claims (1)

[Claims] In a memory circuit having an access port from a control unit (CPU) and a liquid crystal display device (LCD) display port, the access unit from the CPU and the output data from the LCD display port are rotated by 90 degrees. A 2-port memory circuit for LCD display characterized by the following.