ST16C654CJ68 EXAR [Exar Corporation], ST16C654CJ68 Datasheet - Page 5

• Manufacturer Part Number: ST16C654CJ68
• Description: QUAD UART WITH 64-BYTE FIFO AND INFRARED (IrDA) ENCODER/DECODER
• Manufacturer: EXAR [Exar Corporation]

SYMBOL DESCRIPTION
16/-68
A0
A1
A2
A3-A4
CLKSEL
-CS
Symbol
Rev. 4.10
20,50
68
31
34
33
32
30
16
17,64
Pin
100
39
38
37
35
13
36
64
24
23
22
-
-
-
-
Signal
type
I
I
I
I
I
I
I
16/68 Interface Type Select (input with internal pull-up). -
This input provides the 16 (Intel) or 68 (Motorola) bus
interface type select. The functions of -IOR, -IOW, INT A-
D, and -CS A-D are re-assigned with the logical state of this
pin. When this pin is a logic 1, the 16 mode interface 16C554
is selected. When this pin is a logic 0, the 68 mode interface
(68C554) is selected. When this pin is a logic 0, -IOW is re-
assigned to R/-W, RESET is re-assigned to -RESET, -IOR
is not used, and INT A-D(s) are connected in a WIRE-OR”
configuration. The WIRE-OR outputs are connected inter-
nally to the open source IRQ signal output. This pin is not
available on 64 pin packages which operate in the 16 mode
only.
Address-0 Select Bit. Internal registers address selection in
16 and 68 modes.
Address-1 Select Bit. Internal registers address selection in
16 and 68 modes.
Address-2 Select Bit. - Internal registers address selection
in 16 and 68 modes.
Address 3-4 Select Bits. - When the 68 mode is selected,
these pins are used to address or select individual UART’s
(providing -CS is a logic 0). In the 16 mode, these pins are
reassigned as chip selects, see -CSB and -CSC. These pins
are not available on 64 pin packages which operate in the
16 mode only.
Clock Select. - The 1X or 4X pre-scaleable clock is selected
by this pin. The 1X clock is selected when CLKSEL is a logic
1 (connected to VCC) or the 4X is selected when CLKSEL
is a logic 0 (connected to GND). MCR bit-7 can override the
state of this pin following reset or initialization (see MCR bit-
7). This pin is not available on 64 pin packages which
provide MCR bit-7 selection only.
Chip Select. (active low) - In the 68 mode, this pin functions
as a multiple channel chip enable. In this case, all four
5-69
Pin Description
ST16C654/654D