SC16C2550 Philips Semiconductors, SC16C2550 Datasheet - Page 10

• Manufacturer Part Number: SC16C2550
• Description: Dual UART with 16 bytes of transmit and receive FIFOs and infrared (IrDA) encoder/decoder
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 11621
Product data
6.2 Internal registers
Table 3:
The SC16C2550 provides two sets of internal registers (A and B) consisting of
12 registers each for monitoring and controlling the functions of each channel of the
UART. These registers are shown in
holding registers (THR/RHR), interrupt status and control registers (IER/ISR), a FIFO
control register (FCR), line status and control registers (LCR/LSR), modem status
and control registers (MCR/MSR), programmable data rate (clock) control registers
(DLL/DLM), and a user accessible scratchpad register (SPR).
Table 4:
[1]
[2]
[3]
Chip Select
CSA-CSB = 1
CSA = 0
CSB = 0
A2
General register set (THR/RHR, IER/ISR, MCR/MSR, FCR, LSR, SPR)
0
0
0
0
1
1
1
1
Baud rate register set (DLL/DLM)
0
0
Enhanced register set (EFR, Xon/off 1-2)
0
1
1
1
1
These registers are accessible only when LCR[7] is a logic 0.
These registers are accessible only when LCR[7] is a logic 1.
Enhanced Feature Register, Xon1, 2 and Xoff1, 2 are accessible only when the LCR is set to
‘BF(HEX)’.
A1
0
0
1
1
0
0
1
1
0
0
1
0
0
1
1
Serial port selection
Internal registers decoding
A0
0
1
0
1
0
1
0
1
0
1
0
0
1
0
1
Dual UART with 16 bytes of transmit and receive FIFOs and IrDA
Rev. 03 — 19 June 2003
READ mode
Receive Holding Register
Interrupt Status Register
Line Status Register
Modem Status Register
Scratchpad Register
LSB of Divisor Latch
MSB of Divisor Latch
Enhanced Feature Register
Xon1 word
Xon2 word
Xoff1 word
Xoff2 word
Function
none
UART channel A
UART channel B
[2]
Table
[3]
4. The UART registers function as data
WRITE mode
Transmit Holding Register
Interrupt Enable Register
FIFO Control Register
Line Control Register
Modem Control Register
n/a
n/a
Scratchpad Register
LSB of Divisor Latch
MSB of Divisor Latch
Enhanced Feature Register
Xon1 word
Xon2 word
Xoff1 word
Xoff2 word
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
SC16C2550
[1]
encoder/decoder
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