Z80181 Zilog., Z80181 Datasheet - Page 9

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

Zilog
PIA/CTC SIGNALS
Pin Name
PIA17-PIA14 35-38
PIA13-PIA10 31-34
PIA27-20
DS971800500
Pin Number
41-48
Input/Output, Tri-State
I/O
I/O
I/O
Function
Port 1 Data 7-Port 1 Data 4 or CTC ZC/TO3 - ZC/TO0.
These lines can be configured as inputs or outputs on a bit
-by-bit basis. Also, under program control, these bits
become Z80 CTC’s ZC/TO3 - ZC/TO0, and in either timer
or counter mode, pulses are output when the down counter
has reached zero. On reset, these signals function as
PIA17-14 and are inputs.
Port 1 Data 3-Port 1 Data 0 or CTC CLK/TRG3-0. These
lines can be configured as inputs or outputs on a bit by bit
basis. Also, under program control, these bits become Z80
CTC’s CLK/TRG3-CLK/TRG0, and correspond to four
Counter/Timer Channels. In the counter mode, each active
edge causes the downcounter to decrement by one. In
timer mode, an active edge starts the timer. It is program
selectable whether the active edge is rising or falling. On
reset, these signals are set to PIA13-10 as inputs.
Port 2 Data. These lines are configured as inputs or
outputs on a bit-by-bit basis. On reset, they are inputs.
S
MART
A
CCESS
C
ONTROLLER
Z80181
SAC
2-9
™