Z80181 Zilog., Z80181 Datasheet - Page 46

• Manufacturer Part Number: Z80181
• Description: SMART ACCESS CONTROLLER (SAC)
• Manufacturer: Zilog.

Zilog
Data Bus Direction
Table 4 shows the state of the SAC’s data bus when in SAC
bus master condition.
I/O And Memory Transactions
Z80181 Data Bus
(REME Bit = 0)
Z80181 Data Bus
(REME Bit = 1)
Interrupt Acknowledge Transaction
Z80181 Data Bus
(REME Bit = 0)
Z80181 Data Bus
(REME Bit = 1)
2-46
I/O
Write To
On-Chip
Peripherals Peripherals Peripheral Peripheral
(SCC/CTC/ (SCC/CTC/
PIA1/PIA2) PIA1/PIA2)
Out
Out
Intack For
On-Chip
Peripheral
(SCC/CTC)
Z
Out
Table 4. Data Bus Direction (Z181 Is Bus Master)
I/O
Read From
On-Chip
Z
Out
Intack For
Off-Chip
Peripheral
In
In
I/O
Write To
Off-Chip
Out
Out
I/O
Read From To
Off-Chip
In
In
Write
Memory
Out
Out
Read
From
Memory
In
In
S
MART
Refresh
Z
Z
A
CCESS
C
DS971800500
ONTROLLER
Z80181
Mode
Idle
Z
Z
Z80181
SAC
™