TW8835
2 FontRam
FontRam is a memory for the font set image. The font set image will be prepared at the SpiFlash memory (or other external memory)
and it will be download to FontRam. The current FontRam size is a 10KByte. The maximum number of font item depends on the
FontRam size.
10*1024 *8 / (12*18) = 379.2
10*1024*8 / (16*32) = 160
10*1024*8 / (16*32*4) = 40
Table 2.1 maximum font item
2.1 Font index value
After FW downloads font set image from SpiFlash to FontRam, FW use an index value, Font Index.
If FW uses a 0xA0 FontRam index value on 16x26 font set, the real location of this font item will be located on 4160 Byte (0xA0 *
16*26 / 8). Thus, FontRam index 0xA0 means, 0xA0 * R351[6:0] location in FontRam.
R300[4] : font width info. 0:12 pixels 1:16 pixels
R350[4:0] : font height (*2)
R351[6:0]: font size in Byte
Table 3.2 FontRam index related register.
2.2 FontImages
Real FontRam Image
16x26
EndOfFont:0xA0
Logical FontRam Image
with Multi-BPP image
16x26
EndOfFont:0xA0
2BPP=0x60
3BPP=0x6C
4BPP=0x90