Spartan-3A/3AN FPGA Starter Kit Board User Guidewww.xilinx.com 51UG334 (v1.1) June 19, 2008LCD ControllerRFunction SetSets the interface data length, the number of display lines, and the character font.The Starter Kit board supports a single function set with value 0x28.Execution Time: 40 μsSet CG RAM AddressSets the initial CG RAM address.After this command, all subsequent read or write operations to the display are to or fromCG RAM.Execution Time: 40 μsSet DD RAM AddressSets the initial DD RAM address.After this command, all subsequent read or write operations to the display are to or fromDD RAM. The addresses for displayed characters appear in Figure 5-3.Execution Time: 40 μsRead Busy Flag and AddressReads the Busy flag (BF) to determine if an internal operation is in progress, and reads thecurrent address counter contents.BF = 1 indicates that an internal operation is in progress. The next instruction is notaccepted until BF is cleared or until the current instruction is allowed the maximum time toexecute.This command also returns the present value of the address counter. The address counteris used for both CG RAM and DD RAM addresses. The specific context depends on themost recent Set CG RAM Address or Set DD RAM Address command issued.Execution Time: 1 μsWrite Data to CG RAM or DD RAMWrites data into DD RAM if the command follows a previous Set DD RAM Addresscommand, or writes data into CG RAM if the command follows a previous Set CG RAMAddress command.Table 5-3: Shift Patterns According to S/C and R/L BitsDB3(S/C)DB2(R/L) Operation0 0 Shift the cursor position to the left. The address counter is decremented by one.0 1 Shift the cursor position to the right. The address counter is incremented by one.1 0 Shift the entire display to the left. The cursor follows the display shift. Theaddress counter is unchanged.1 1 Shift the entire display to the right. The cursor follows the display shift. Theaddress counter is unchanged.
