83Plus:BCALLs:4CED
From WikiTI
Synopsis
Official Name: ClearRow
BCALL Address: 4CED
Clears eight consecutive LCD display drive rows
Inputs
- A = LCD display driver row coordinate (0x80 – 0xBF)
Outputs
- Eight pixel rows cleared
- Driver left in X increment mode (the default)
Destroys
- AF, B, DE
Comments
This routine requires A to be in LCD display driver row (X) coordinates, which have a valid range between 0x80 – 0xBF, with the top pixel row equal to 0x80 and the bottom pixel row equal to 0xBF. Passing in a value for A outside this range will cause unpredictable results and probably a lockup. This routine erases eight consecutive rows, so if you pass in A = 0x88, the 9th – 16th pixel rows from the top of the display are erased. If you pass in a value between 0xB9 – 0xBF, the erased rows wrap back to the top of the display. In normal usage, if you are erasing a line of large text, the A value should be a multiple of 0x08.
