DAN-136 Datasheet, PDF (2/5 Pages) Exar Corporation – EXAR XR16L580 COMPARED

DATA COMMUNICATIONS APPLICATION NOTE
DAN137
PIN NAMES
RCLK
-BAUDOUT
CS0
CS1
IOR
IOW
-TXRDY
-RXRDY
-AS
-DDIS
-OP1
-OP2
TABLE 1: LEGACY SIGNALS IN THE TL16C550C, 48-TQFP PACKAGE
48-TQFP PIN#
DESCRIPTION
5
The RCLK needs to be connected to the BAUDOUT external to the uart on the
12
TL16C550C. This is done internally in the XR16L580.
9
These are redundant Chip Select signals on the TL16C550C and have been removed
10
in the XR16L580.
20
These are redundant control signals on the TL16C550C and have been removed in the
17
XR16L580.
23
These are status indicator outputs on the TL16C550C that are rarely used in most appli-
29
cations and have been removed in the XR16L580.
24
The Address Strobe signal is used to latch the address inside the uart on the
TL16C550C. The XR16L580 automatically latches the address internally and hence
this signal has been removed.
22
Data Disable output. Rarely used in today’s applications.
34
General Purpose outputs. Rarely used in today’s applications.
31
FIGURE 1. CRYSTAL OSCILLATOR CIRCUITRY DIFFERENCES
TL16C550CPT/PFB
XR16L580IM
XTAL1
C1
10-30 pF
XTAL2
R2
1 ΜΩ
Y1
C2
40-60 pF
R1
1.5 KΩ
1.8432
MHz
to
16
MHz
XTAL1
XTAL2
R2
500 ΚΩ − 1 ΜΩ
Y1
C1
22-47 pF
C2
22-47 pF
R1
0-120 Ω
(Optional)
1.8432
MHz
to
24
MHz
2