OM13008,598 NXP Semiconductors, OM13008,598 Datasheet - Page 149

• Manufacturer Part Number: OM13008,598
• Description: BOARD LPC XPRESSO LPC122X
• Manufacturer: NXP Semiconductors
• Series: LPCXpressor

Specifications of OM13008,598

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 568-6642; OM13008

NXP Semiconductors
UM10441
User manual
9.5.12.1 Auto-baud
Table 152. Auto-baud Control Register (ACR - address 0x4000 8020) bit description
The UART auto-baud function can be used to measure the incoming baud-rate based on
the ”AT" protocol (Hayes command). If enabled the auto-baud feature will measure the bit
time of the receive data stream and set the divisor latch registers DLM and DLL
accordingly.
Auto-baud is started by setting the ACR Start bit. Auto-baud can be stopped by clearing
the ACR Start bit. The Start bit will clear once auto-baud has finished and reading the bit
will return the status of auto-baud (pending/finished).
Two auto-baud measuring modes are available which can be selected by the ACR Mode
bit. In mode 0 the baud-rate is measured on two subsequent falling edges of the UART
RX pin (the falling edge of the start bit and the falling edge of the least significant bit). In
mode 1 the baud-rate is measured between the falling edge and the subsequent rising
edge of the UART RX pin (the length of the start bit).
31:10 -
Bit
0
1
2
7:3
8
9
Symbol
START
MODE
AUTORESTART
-
ABEOINTCLR
ABTOINTCLR
All information provided in this document is subject to legal disclaimers.
Rev. 1.1 — 10 March 2011
Value Description
0
1
0
1
0
1
0
1
0
1
Start bit. This bit is automatically cleared after
auto-baud completion.
Auto-baud stop (auto-baud is not running).
Auto-baud start (auto-baud is running). Auto-baud run
bit. This bit is automatically cleared after auto-baud
completion.
Auto-baud mode select bit.
Mode 0.
Mode 1.
Start mode.
No restart
Restart in case of time-out (counter restarts at next
UART RX falling edge)
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
End of auto-baud interrupt clear bit (write only
accessible).
Writing a 0 has no impact.
Writing a 1 will clear the corresponding interrupt in the
IIR.
Auto-baud time-out interrupt clear bit (write only
accessible).
Writing a 0 has no impact.
Writing a 1 will clear the corresponding interrupt in the
IIR.
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
Chapter 9: LPC122x UART0 with modem control
UM10441
© NXP B.V. 2011. All rights reserved.
149 of 442
Reset
value
0
0
0
0
0
0
0