TL16PNP550A Datasheet, PDF (21/40 Pages) Texas Instruments – ASYNCHRONOUS COMMUNICATIONS ELEMENT WITH PLUG-AND-PLAY (PnP) AND AUTOFLOW CONTROL

TL16PNP550A
ASYNCHRONOUS COMMUNICATIONS ELEMENT
WITH PLUG-AND-PLAY (PnP) AND AUTOFLOW CONTROL
SLLS190B – MARCH 1995 – REVISED MARCH 1996
PRINCIPLES OF OPERATION
PnP registers
PnP card standard registers are divided into three parts: card control, logical device control, and logical device
configuration. There is exactly one of each card control register on each ISA card. Card control registers are
used for global functions that control the entire card (see Table 5). Logical device control registers and logical
device configuration registers are repeated for each logical device. Since the TL16PNP550A has one logical
device (ACE) and it is intended only for I/O applications, not all the configuration registers are implemented.
ADDRESS PORT
VALUE
0×00
0×01
0×02
0×03
0×04
0×05
0×06
0×07
Table 5. PnP Card Control Registers
REGISTER NAME VALUE
READ/WRITE
CAPABILITY
POWER UP
SET RD_DATA PORT
Write only
00 00 00 00
Writing to this location modifies the address port used for reading from the PnP ISA card. Writing to this register is
only allowed when the card is in the isolation state.
Bit<7:0> Become I/O port address bits [9:2].
SERIAL ISOLATION
Read only
00 00 00 00
A read to this register causes a card in the isolation state to compare one bit of the board ID.
CONFIGURATION CONTROL
Write only
0 00
This 3-bit register consists of three independent commands, which are activated by setting their corresponding
register bits. These bits are automatically cleared by the hardware after the commands execute.
Bit<2> Setting this bit causes the card to clear its CSN and RD DATA port.
Bit<1> Setting this bit causes the card to enter the wait for key state, but the card CSN is
preserved and the logical device (ACE) is unaffected.
Bit<0> Setting this bit resets the logical device (ACE) configuration registers to their default
state and the CSN is preserved.
WAKE[CSN]
Write only
00 00 00 00
A write to this register, if the write data [7:0] matches the card CSN, causes the card to go from the sleep state to
either the isolation state, if the write data for this command is zero, or the configuration state if the write data is not
zero. The pointer to the SERIAL IDENTIFIER is reset. This register is write only.
RESOURCE DATA
Read only
00 00 00 00
A read from this address reads the next byte of resource information from the EPROM. The STATUS register must
be polled until its bit<0> is set, before this register may be read.
STATUS
Read only
0
Bit<0>
A 1-bit register that when set, indicates it is okay to read the next data byte from the RESOURCE
DATA register.
CARD SELECT NUMBER
Read/write
00 00 00 00
A write to this address sets a card CSN, which is uniquely assigned to this card after the serial identification process,
so each card may be individually selected during a WAKE [CSN] command.
LOGICAL DEVICE NUMBER
Read
00 00 00 00
This register has a read-only value of 0 × 00, since the card has only 1 logical device.
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