Serial Interface
MPC885 PowerQUICC Family Reference Manual, Rev. 2
20-38
Freescale Semiconductor
These registers are affected by HRESET but are not affected by SRESET.
Table 20-13
describes the
BRGCn fields.
0
13
14
15
Field
—
RST
EN
Reset
0
R/W
R/W
Addr
0x9F0 (BRGC1), 0x9F4 (BRGC2), 0x9F8 (BRGC3), 0x9FC (BRGC4)
16
17
18
19
30
31
Field
EXTC
ATB
CD
DIV16
Reset
0
R/W
R/W
Addr
0x9F2 (BRGC1), 0x9F6 (BRGC2), 0x9FA (BRGC3), 0x9FE (BRGC4)
Figure 20-30. Baud Rate Generator Configuration Registers (BRGCn)
Table 20-13. BRGC
n
Field Descriptions
Bits
Name
Description
0–13
—
Reserved, should be cleared.
14
RST
Reset BRG. Performs a software reset of the BRG identical to that of an external reset. A reset
disables the BRG and drives BRGO high. This is externally visible only if BRGO is connected to the
corresponding parallel I/O pin.
0 Enable the BRG
1 Reset the BRG (software reset)
15
EN
Enable BRG count. Used to dynamically stop the BRG from counting—useful for low-power modes.
0 Stop all clocks to the BRG
1 Enable clocks to the BRG
16–17
EXTC External clock source. Selects the BRG input clock.
00 BRGCLK (internal clock generated by the clock synthesizer in the SIU).
01 CLK2
10 CLK6
11 Reserved
18
ATB
Autobaud. Selects autobaud operation for BRG
n on the corresponding RXDn. ATB must remain zero
until the SCC receives the three Rx clocks. Then the user must set ATB to obtain the correct baud
rate. After the baud rate is obtained and locked, it is indicated by setting AB in the UART event
register. See
Section 20.4.2, “Autobaud Operation on the SCC UART.”
0 Normal operation of the BRG
1 When RXD goes low, the BRG determines the length of the start bit and synchronizes the BRG
to the actual baud rate.
Summary of Contents for PowerQUICC MPC870
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Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
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Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
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