SAB 82525
SAB 82526
SAF 82525
SAF 82526
Pin Definitions and Functions (cont’d)
Pin No.
Symbol Input (I)
Function
Output (O)
P-LCC P-MQFP
18
23
IM1
I
Input Mode 1
Connecting this pin to either VSS or VDD the bus interface can
be adapted to either Siemens/Intel or Motorola
environment.
IM1 = LOW: Intel bus mode
IM1 = HIGH: Motorola bus mode
19
24
ALE/
IM0
I
Address Latch Enable (Intel bus mode)
A high on this line indicates an address on the external
address/data bus, which will select one of the HSCX’s
internal registers. The address is latched by the HSCX with
the falling edge of ALE. This allows the HSCX to be directly
connected to a CPU with multiplexed address/data bus
compatible to SAB 82520 HSCC.
The address input pins A0-A6 must be externally
connected to the data bus pins (D0-D6 for 8-bit CPU’s, D1-
D7 for 16-bit CPU’s, i.e. multiply all internal register
addresses by 2).
This pin should be connected to high for a de-multiplexed
bus.
Input Mode 0, Motorola bus mode
In Motorola Bus Mode, the level at this pin determines the
function of the IC1 pin (see description of pin 6).
20
25
V
SS
I
I
Ground
27
26
25
24
23
22
21
32
31
30
29
28
27
26
A0
A1
A2
A3
A4
A5
A6
Address Bus
These inputs interface with seven bits of the system’s
address bus to select one of the internal registers for read
or write.
They are usually connected at A0-A6 in 8-bit systems or at
A1-A7 in 16-bit systems.
Semiconductor Group
12
SIEMENS [ Siemens Semiconductor Group ]
