MC68340AB16E Datasheet, PDF (321/441 Pages) Motorola, Inc – Integrated Processor with DMA User’s Manual

Freescale Semiconductor, Inc.
7.4.1.6 CLOCK-SELECT REGISTER (CSR). The CSR selects the baud rate clock for the
channel receiver and transmitter. This register can only be written when the serial module
is enabled (i.e., the STP bit in the MCR is cleared).
NOTE
This register should only be written after the external crystal is
stable (XTAL_RDY bit of the ISR is zero).
CSRA, CSRB
$711, $719
7
6
5
4
3
2
1
0
RCS3 RCS2 RCS1 RCS0 TCS3 TCS2 TCS1 TCS0
RESET:
0
0
0
0
0
0
0
0
Write Only
Supervisor/User
RCS3–RCS0—Receiver Clock Select
These bits select the baud rate clock for the channel receiver from a set of baud rates
listed in Table 7-4. The baud rate set selected depends upon the auxiliary control
register (ACR) bit 7. Set 1 is selected if ACR bit 7 = 0, and set 2 is selected if ACR bit
7 = 1. The receiver clock is always 16 times the baud rate shown in this list, except
when SCLK is used.
Table 7-4. RCSx Control Bits
RCS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
RCS2 RCS1 RCS0 Set 1
Set 2
0
0
0
50
75
0
0
1
110
110
0
1
0
134.5
134.5
0
1
1
200
150
1
0
0
300
300
1
0
1
600
600
1
1
0
1200
1200
1
1
1
1050
2000
0
0
0
2400
2400
0
0
1
4800
4800
0
1
0
7200
1800
0
1
1
9600
9600
1
0
0
38.4k
19.2k
1
0
1
76.8k
38.4k
1
1
0 SCLK/16 SCLK/16
1
1
1
SCLK/1 SCLK/1
7-26
MC68340 USER’S MANUAL
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