• Memory for system setting of sprite IC, built in VDP1 separately from VRAM and frame buffer.
  
• There are read-only (read-only) registers and write-only (write-only) registers.
  
• The write-only register is used to control the frame buffer display. Select TV mode, specify display switching and drawing trigger, define erase light fill data and area. You can also forcibly terminate drawing.
  
• Read-only registers are used as help information during program development. You can know the address of the last command table processed and the address of the command table currently being processed.
  
• Be sure to perform read / write access from the CPU in word units.
  
• Do not use DMA burst transfer to access system registers.
  
• Besides the plot trigger register (PTMR), values ​​for write-only system registers are undefined after power-on or reset, so be sure to set a value with the CPU. Indefinite data is displayed from the frame buffer until an appropriate value is set.
  
• Set the unused bits of the write-only system register to 0.

Table 2.1 System Register

Address	Name	Content	Access
100000H	TVHR	TV mode selection	Write only (word)
100002H	FBCR	Frame buffer switching mode	Write only (word)
100004H	PTMR	Plot trigger	Write only (word)
100006H	EWDR	Erase Light Data	Write only (word)
100008H	EWLR	Erase light upper left coordinates	Write only (word)
10000AH	EWRR	Erasing light lower right coordinate	Write only (word)
10000CH	ENDR	Forcibly finish drawing	Write only (word)
100010H	EDSR	Transfer end status	Read only (word)
100012H	LOPR	Processing suspension table address	Read only (word)
100014H	COPR	Current processing table address	Read only (word)
100016H	MODR	Mode state	Read only (word)