OX16PCI954_05 Datasheet, PDF (46/73 Pages) Oxford Semiconductor – Integrated Quad UART and PCI interface

OXFORD SEMICONDUCTOR LTD.
OX16PCI954
values in bits-per-second (bps) that are obtained if the
divisor latch = 0x01 and the Prescaler is set to 1.
The OX16PCI954 has the facility to operate at baud-rates
up to 15 Mbps in normal mode.
Table 26 indicates how the value in the register
corresponds to the number of clock cycles per bit. TCR[3:0]
is used to program the clock. TCR[7:4] are unused and will
return “0000” if read.
TCR[3:0]
Clock cycles per bit
0000 to 0011
16
0100 to 1111
4-15
Table 26: TCR Sample Clock Configuration
Use of the TCR does not require the device to be in 650 or
950 mode although only drivers that have been written to
take advantage of the 950 mode features will be able to
access this register. Writing 0x01 to the TCR will not switch
the device into 1x isochronous mode, this is explained in
the following section. (TCR has no effect in isochronous
mode). If 0x01, 0x10 or 0x11 is written to TCR the device
will operate in 16x mode.
Reading TCR will always return the last value that was
written to it irrespective of mode of operation.
Clock
Frequency
(MHz)
1.8432
7.3728
14.7456
18.432
32.000
33.000
40.000
50.000
60.000
CPR value
0x08 (1)
0x20 (4)
0x40 (8)
0x50 (10)
0x8B (17.375)
0x8F (17.875)
0xAE (21.75)
0xD9 (27.125)
0xFF (31.875)
Effective
crystal
frequency
1.8432
1.8432
1.8432
1.8432
1.8417
1.8462
1.8391
1.8433
1.8824
Error from
1.8432MHz
(%)
0.00
0.00
0.00
0.00
0.08
0.16
0.22
0.01
2.13
Max. Baud rate
with CPR = 1,
TCR = 16
115,200
460,800
921,600
1,152,000
2,000,000
2,062,500
2,500,000
3,125,000
3,750,000
Max. Baud rate
with CPR = 1,
TCR = 4
460,800
1,843,200
3,686,400
4,608,000
8,000,000
8,250,000
10,000,000
12,500,000
15,000,000
Table 27: Example clock options and their associated maximum baud rates
Sampling TCR
Clock Value
16 0x00
15 0x0F
14 0x0E
13 0x0D
12 0x0C
11 0x0B
10 0x0A
9 0x09
8 0x08
7 0x07
6 0x06
5 0x05
4 0x04
1.8432
115,200
122,880
131,657
141,785
153,600
167,564
184,320
204,800
230,400
263,314
307,200
368,640
460,800
System Clock (MHz)
7.372 14.7456 18.432
32
40
50
60
460,750 921,600 1.152M 2.00M 2.50M 3.125M 3.75M
491,467 983,040 1,228,800 2,133,333 2,666,667 3,333,333 4.00M
526,571 1,053,257 1,316,571 2,285,714 2,857,143 3,571,429 4,285,714
567,077 1,134,277 1,417,846 2,461,538 3,076,923 3,846,154 4,615,384
614,333 1,228,800 1,536,000 2,666,667 3,333,333 4,166,667 5.00M
670,182 1,340,509 1,675,636 2,909,091 3,636,364 4,545,455 5,454545
737,200 1,474,560 1,843,200 3.20M 4.00M 5.00M 6.00M
819,111 1,638,400 2,048,000 3,555,556 4,444,444 5,555,556 6,666,667
921,500 1,843,200 2,304,000 4.00M 5.00M 6.25M 7.50M
1,053,143 2,106,514 2,633,143 4,571,429 5,714,286 7,142,857 8,571428
1,228,667 2,457,600 3,072,000 5,333,333 6,666,667 8,333,333 10.00M
1,474,400 2,949,120 3,686,400 6.40M 8.00M 10.00M 12.00M
1,843,000 3,686,400 4,608,000 8.00M 10.00M 12.50M 15.00M
Table 28: Maximum Baud Rates Available at all ‘TCR’ Sampling Clock Values
DS-0029 Jul 05
External—Free Release
Page 46