Intel
®
81341 and 81342—UARTs
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
908
Order Number: 315037-002US
15.4.13 UART x Auto-Baud Count Register
The Auto-Baud Count register stores the number of 33.334 MHZ clock cycles within a
start bit pulse. This value is then used by the processor or auto-baud circuitry within
the UART to calculate the baud rate. When Auto-Baud mode and Auto-Baud Interrupts
are enabled, the UART interrupt the processor with the Auto-Baud Lock Interrupt after
it has written the count value into the ACR. The value is written regardless of the state
of the auto-baud UART program bit.
Table 580. UART x Auto-Baud Count Register - (UxACR)
Bit
Default
Description
31:16
0000h
Reserved
15:0
0000h
ACR[15:0]: Number of 33.334 MHz clock cycles within a start bit pulse.
PC
I
IO
P
A
tt
ri
bu
te
s
A
tt
ri
bu
te
s
28
24
20
16
12
8
4
0
31
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
Unit #
01
Intel XScale
®
Core internal bus address
+232CH (DLAB=x)
+236CH (DLAB=x)
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible