lcd-Bare Metal Vedon

First look at the LCD interface how to connect, at this time to find the LCD schematic, see the line arrangement and by looking at the LCD manual to read each pin function assignment.

The reading process of the hardware Development Board is a process of accumulating experience.

The hardware schematic connection is very simple, just like a building block together. The corresponding protocol of the LCD must also meet the two requirements of the communication.

LCD Each line has how many points, an electronic gun in the back one to hit this point, through the clock vclk to determine the interval, a line after the completion of a vline such a horizontal direction of the synchronization signal to go to the next line, until all the points are finished after the need to return to the original position, This is the time to synchronize the models horizontally. For color problems We can use vd0-23 to get the color data up to the screen. The de pin is the data enable PIN.

The GPIO provides a backlight voltage through a backlight circuit, providing a voltage to the LCD itself via a power supply circuit. And then through the above LCD controller corresponding to the configuration of the pin can realize the data.

Assign a video memory to the SDRM and then import the data into the LCD controller for the corresponding operation

1. See schematic: 2440 and the external chip pin docking can be connected is the same pin docking.
2. Figuring out the interface protocol: how the data is transmitted, how the pin fits
3. Set timing: 2440 each signal sent, to let the external chip can reflect the
4. Look at the 2440 manual. What parameters can be set, meaning of these parameters (in CLK)
5. Look at the peripheral chip manual and figure out the range of values (in seconds) for these parameters
6. Calculate the register value of 2440 based on the two steps above

Memory-like interface: Ram-line

SDRAM, NOR, network card

Data line, Address line is two basic things, but we know that the above several chips using the same address line and data line, how to do, need a CS chip selector pin to select the corresponding chip, when the high power, the corresponding PIN will respond accordingly.

Q 1:

Q 2: Does the chip selection pin need to be set manually?

Answer 2: no need. When the CPU accesses an address, the CPU sends an address signal to the memory controller, and the memory controller makes the corresponding

So let's say why our memory address is 30000000, because we have this time the memory controller to select the address, corresponding to the corresponding chip selection signal, select the memory chip.

The address range of a single chip pin corresponds to a bank, a bank size of 128M, is 2 27 times, that is, 27 address lines are required.

The CPU is 32 bits, but does not represent 32 address lines. CPU access a address, then the previous 0 to 26 bits appear on the address line, and the remaining 27-32 bits is useless, that is, 5 address line is useless, is idle, of course, this discussion is the 2440 Development Board for the storage discussion.

OE is the output signal, we are write enable, re is read enable. Requires 2440 to have a memory controller and CPU,CPU send a

lcd-Bare Metal Vedon