HD64F2149 Datasheet, PDF (601/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

using interrupts. Table 18A.6 lists the conditions that set and clear GA20 (P81). Figure 18A.2
shows the GA20 output in flowchart form. Table 18A.7 indicates the GA20 output signal values.
Table 18A.6 GA20 (P81) Set/Clear Timing
Pin Name
GA20
(P81)
Setting Condition
Rising edge of the host’s write signal
(IOW) when bit 1 of the written data is 1
and the data follows an H'D1 host
command
Clearing Condition
Rising edge of the host’s write signal
(IOW) when bit 1 of the written data is 0
and the data follows an H'D1 host
command
Also, when bit FGA20E in HICR is cleared
to 0
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 18A.2 GA20 Output
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