
TL16PC564B, TL16PC564BLV
PCMCIA UNIVERSAL ASYNCHRONOUS RECEIVER TRANSMITTER
SLLS225A – MARCH 1996 – REVISED FEBRUARY 1998
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Terminal Functions
TERMINAL
INTER-
FACE
I/O
DESCRIPTION
NAME
ALE (AS)
NO.
26
S
I
Address-latch enable/address strobe. ALE(AS) is an address-latch enable in the Intel mode
and an address strobe in the Zilog mode. ALE (AS) is active high for an Intel subsystem and
active low for a Zilog subsystem.
Arbitration clock output. ARBCLKO is equal to the input on ARBCLKI divided by the
binary-coded divisor input on ARBPGM (1–0).
ARBCLKO
7
M
O
ARBCLKI
5
M
I
Arbitration clock input. ARBCLKI is the base clock used in arbitration for the attribute memory
DRAM and the reset validation circuitry.
ARBPGM0
ARBPGM1
8
9
M
I
Arbitration clock divisor program. These two bits set the divisor for ARBCLKI. Divide by 1, 2,
4, and 8 are available.
Baud output. BAUDOUT is an active-low 16
×
signal for the transmitter section of the UART.
The clock rate is established by the reference clock (UARTCLK) frequency divided by a divisor
specified by the baud generator divisor latches. BAUDOUT may also be used for the receiver
section by tying this output to the RCLK input.
Card enable 1 and card enable 2 are active-low signals. CE1 enables even-numbered
address bytes, and CE2 enables odd-numbered address bytes. A multiplexing scheme based
on HA0, CE1, and CE2 allows an 8-bit host to access all data on HD0 through HD7 if desired.
These signals have internal pullup resistors.
Chip select. CS is the active-low chip select from the Zilog or Intel microcontroller.
Clear to send. CTS is an active-low modem status signal whose condition can be checked by
reading bit 4 (CTS) of the modem status register (MSR). Bit 0 (delta clear to send) of the MSR
indicates that the signal has changed states since the last read from the MSR. If the
modem-status interrupt is enabled when CTS changes states, an interrupt is generated.
Data carrier detect. DCD is an active-low modem-status signal whose condition can be
checked by reading bit 7 (DCD) of the MSR. Bit 3 (delta data carrier detect) of the MSR
indicates that the signal has changed states since the last read from the MSR. If the
modem-status interrupt is enabled when DCD changes states, an interrupt is generated.
Data set ready. DSR is an active-low modem status signal whose condition can be checked
by reading bit 5 (DSR) of the MSR. Bit 1 (delta data set ready) of the MSR indicates that the
signal has changed states since the last read from the MSR. If the modem-status interrupt is
enabled when DSR changes states, an interrupt is generated.
Data terminal ready. DSD is an active-low signal. When active, DTR informs the modem or
data set that the UART is ready to establish communication. DTR is placed in the active state
by setting the DTR bit 0 of the modem control register (MCR) to a high level. DTR is placed
in the inactive state either as a result of a reset, doing a loop-mode operation, or resetting bit
0 (DTR) of the MCR.
BAUDOUT
38
U
O
CE1
CE2
94
62
H
I
CS
CTS
32
49
S
U
I
I
DCD
48
U
I
DSR
46
U
I
DTR
34
U
O
EXTEND
1
U
I
FIFO extend. When EXTEND is high, the UART is configured as a standard TL16C550 with
16-byte transmit and receive FIFOs. When EXTEND is low and FIFO control register (FCR)
bit 5 is high, the FIFOs are extended to 64 bytes and the receiver-interrupt trigger levels adjust
accordingly. EXTEND low in conjunction with FIFO control register (FCR) bit 4 set high
enables the auto-RTS function.
GND
4,6,13,16,30,
39,41,43,54,
66,68,69,80,91
M
Common ground
Host = H, Subsystem = S, UART = U, Miscellaneous = M