ST16C552 Exar Corporation, ST16C552 Datasheet - Page 10

• Manufacturer Part Number: ST16C552
• Description: DUAL UART WITH 16-BYTE FIFO AND PARALLEL PRINTER PORT
• Manufacturer: Exar Corporation

ST16C552/552A
Note 1* The General Register set is accessible only when CS A or CS B is a logic 0.
Note 2* The Baud Rate register set is accessible only when CS A or CS B is a logic 0 and LCR bit-7 is a logic 1.
Note 3*: Printer Port Register set is accessible only when -CSP is a logic 0 in conjunction with the states of the
interface signal BIDEN and Printer Control Register bit-5 or IOSEL register.
Rev. 3.40
A2
0
0
0
0
1
1
1
1
0
0
X
X
X
Table 4, INTERNAL REGISTER DECODE
General Register Set (THR/RHR, IER/ISR, MCR/MSR, LCR/LSR, SPR): Note 1*
Baud Rate Register Set (DLL/DLM): Note *2
Printer Port Set (PR/SR/IOSEL/COM/CON): Note *3
A1
0
0
1
1
0
0
1
1
0
0
0
0
1
A0
0
1
0
1
0
1
0
1
0
1
0
1
0
READ MODE
Receive Holding Register
Interrupt Status Register
Line Status Register
Modem Status Register
Scratchpad Register
LSB of Divisor Latch
MSB of Divisor Latch
PORT REGISTER
STATUS REGISTER
COMMAND REGISTER
10
WRITE MODE
Transmit Holding Register
Interrupt Enable Register
FIFO Control Register
Line Control Register
Modem Control Register
Scratchpad Register
LSB of Divisor Latch
MSB of Divisor Latch
PORT REGISTER
I/O SELECT REGISTER
CONTROL REGISTER