HD64F2145 Datasheet, PDF (580/829 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Start
Host write
No
H'D1 command
received?
Yes
Wait for next byte
Host write
No
Data byte?
Yes
Write bit 1 of data byte
to DR bit of P81/GA20
Figure 19.4 GA20 Output
Rev. 2.0, 08/02, page 540 of 788