|&BDxx||0||0||1||Write to selected internal 6845 register||Write only
|-
|&BExx||0||1||0||(note * CRTCs 0/2: -* CRTC 1): Read Status Register* CRTCs 3/4: Read from selected internal 6845 register||Read only
|-
|&BFxx||0||1||1||Read from selected internal 6845 register||Read only
|}
'''NOTES''' 1. The function of this I/O port is dependant on the CRTC type 2. The CRTC is not connected to the CPU's RD and WR pins, so it cannot detect the bus's I/O direction. Therefore, executing an IN instruction to the select or write functions causes the CRTC to write the unpredictable data provided by the high-impedance bus to its registers.
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