Panasonic JB-3300 Technical Manual page 76

[7.2] DMA Overrun Error
DMA Overrun
FD Control Command
Register
FDC (uwPD765C)
DMA, INT Enable :
Gate Circuit
DMAC (8237A-5)
Circuit
DACK Gate Circuit
Error
Ss
+ DMAGATE No
Signal
OK? Y:4F-15
Yes
Is No
DC DRQ Signal
OK? Y¥:9G-14
Yes
Is No
DREQ2 Signal
OK? J Y:4F-11
Yes
Is
*DACK2 Signal >—V2
2
OK: ¥:12F-6
Yes
Is
FDC DACK No
>?
Input: Y:9G-15
Is
*TC Signal He
>
Ov oe
Yes
DMAC Circuit
TC Gate Circuit
FDC (uPD765AC)
Data Bus
Figure 9-15 (2/2)