µPD720130
2.4 Combo Mode Function
The µPD720130 can be used to realize that two IDE controller chips control one target IDE device in one
system. To realize IDE bus arbitration between two IDE controller chips, the µPD720130 has CMB_BSY and
CMB_STATE. Combo mode is enabled when PWR = 0 and CLC = 1.
CMB_BSY and CMB_STATE connect to other IDE controller chip as follows.
Figure 2-1. CMB_BSY and CMB_STATE Connection between Two IDE Controller Chips
µ PD720130
Other IDE controller
CMB_STATE
CMB_BSY
IDE Bus Grant
IDE Bus Request
Pin Name
CMB_STATE
CMB_BSY
Table 2-5. Description of CMB_BSY and CMB_STATE
Direction
IN
OUT
Value
0
1
0
1
Description
Other IDE controller does not require or does not use IDE bus.
Other IDE controller requires or is using IDE bus.
The µPD720130 does not require or does not use IDE bus.
The µPD720130 requires or is using IDE bus.
Data Sheet S16302EJ3V0DS
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