| ??? 01/22/08 15:32 Read: times |
#149852 - take another look at the datasheet Responding to: ???'s previous message |
Andy Neil said:
http://en.wikipedia.org/wiki/Write_Only_Memory
Ap Charles said:
Also I dont know any RAM where you cant Read data, If it exists please update me. Generally speaking, a display is an output device - so you wouldn't necessarily expect to be able to read-back anything that you'd sent to it? Of course, the RAM itself can be read and written - it could just be that no interface is provided for the host to read-back what it wrote...? A bit like the 8051's UART transmit register: once you've written to it, you can't read-back what you wrote. Apparently you need to have another look at the datasheet, Andy. There are devices to which you can only write, and the transmit register of a UART is a reasonable example, but an LCD with a HD44780-style controller is not one of them. Every character has an address, and, if you write a specific address to the device, and then write a character to that address, either explicitly or implicitly, you can read it back. All you have to do is to follow the instructions. RE |
